Segment Reporting [Abstract] SEGMENT REPORTING Segment Reporting Disclosure [Text Block] Related Party Transactions [Abstract] RELATED-PARTY TRANSACTIONS Related Party Transactions Disclosure [Text Block] Investments, Debt and Equity Securities [Abstract] INVESTMENTS Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Debt Disclosure [Abstract] Outstanding Debt Obligations Schedule of Debt [Table Text Block] Redemption Prices as Percentage of Principal Amount Schedule of Redemption Prices as Percentage of Principal Amount [Table Text Block] Schedule of Redemption Prices as Percentage of Principal Amount [Table Text Block] Valuation and Qualifying Accounts [Abstract] Schedule II - Valuation and Qualifying Accounts Schedule of Valuation and Qualifying Accounts Disclosure [Text Block] Accounting Policies [Abstract] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Plan Name [Axis] Plan Name [Axis] Plan Name [Domain] Plan Name [Domain] 2013 Plan 2013 Incentive Compensation Plan [Member] 2013 Incentive Compensation Plan Award Type [Axis] Award Type [Axis] Award Type Equity Award [Domain] Restricted Stock Units Restricted Stock Units (RSUs) [Member] Performance Shares Performance Shares [Member] Market Stock Units Market Stock Units [Member] Market stock units (MSUs) as awarded by a company to their employees as a form of incentive compensation. Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum Minimum [Member] Maximum Maximum [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Number of shares authorized (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized Restricted stock units, conversion ratio Share-based Compensation Arrangement by Share-based Payment Award, Conversion Ratio Share-based Compensation Arrangement by Share-based Payment Award, Conversion Ratio Vesting period Share-Based Compensation Restricted Stock Units Vesting Period Share-Based Compensation Restricted Stock Units Vesting Period Cliff vesting number of shares earned, minimum (in shares) Cliff Vesting, Number Of Shares Earned, Range, Minimum Cliff Vesting, Number Of Shares Earned, Range, Minimum Cliff vesting target range percentage, maximum Cliff Vesting Target Range Percentage Cliff Vesting Target Range Percentage Vesting period of certain equity-based compensation Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Number of plan variations Share-based Compensation, Number of Plans Share-based Compensation, Number of Plans Number of calendar days preceding the vesting date to the comparable average common stock price in the year immediately preceding the grant date Number Of Calendar Days Preceding End Of Fiscal Year Prior To Vesting Date With Maximum Quotient Number Of Calendar Days Preceding End Of Fiscal Year Prior To Vesting Date With Maximum Quotient Maximum common stock decline before no shares are earned Minimum Percentage Multiplier Of Msus Minimum Percentage Multiplier Of Msus Valuation and Qualifying Accounts Disclosure [Table] Valuation and Qualifying Accounts Disclosure [Table] Valuation Allowances and Reserves Type [Axis] Valuation Allowances and Reserves Type [Axis] Valuation Allowances and Reserves [Domain] Valuation Allowances and Reserves [Domain] Premiums receivable Allowance for Uncollectible Premiums Receivable [Member] Medical advances Allowance for Uncollectible Medical Advances [Member] A valuation allowance for the amount owed to an insurance company for medical advances that the company expects to be uncollectible. Valuation and Qualifying Accounts Disclosure [Line Items] Valuation and Qualifying Accounts Disclosure [Line Items] Deducted from assets: Deducted from assets: [Abstract] Allowance for uncollectible accounts: Movement in Valuation Allowances and Reserves [Roll Forward] Balance at Beginning of Period Valuation Allowances and Reserves, Balance Charged to Costs and Expenses Valuation Allowances and Reserves, Additions for Charges to Cost and Expense Write Offs Valuation Allowances and Reserves, Deductions Balance at End of Period Earnings Per Share [Abstract] Weighted-average common shares outstanding — basic (in shares) Weighted Average Number of Shares Outstanding, Basic Dilutive effect of outstanding stock-based compensation awards (in shares) Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Weighted-average common shares outstanding — diluted (in shares) Weighted Average Number of Shares Outstanding, Diluted Anti-dilutive stock-based compensation awards excluded from computation (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Other Net Payables to Government Partners Schedule of other payables to government partners [Table Text Block] Tabular disclosure of the amounts due to government agencies under various contractual and plan arrangements. Funds (Payable) Receivable for the Benefit of Members, Net " Funds Receivable Held For The Benefit Of Members [Table Text Block] Tabular disclosure of funds receivable or held for the benefit of members that includes catastrophic reinsurance, low-income cost sharing and coverage gap discount subsidies from the Center for Medicare and Medicaid Services in connection with the Medicare Part D program. Business Combinations [Abstract] Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] Universal American Universal American [Member] Universal American [Member] Business Acquisition [Line Items] Business Acquisition [Line Items] Assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets [Abstract] Cash and cash equivalents Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents Investments, including restricted investments Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Investments Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Investments Premiums receivable, net Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Premiums Receivable Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Premiums Receivable Pharmacy rebates receivable, net, and other current assets Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Pharmacy Rebates Receivable And Other Current Assets Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Pharmacy Rebates Receivable and Other Current Assets Property, equipment and capitalized software, net Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment Goodwill Goodwill Other intangible assets, net Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill Assets of discontinued operations Business Combinations, Recognized Identifiable Assets Acquired And Liabilities Consumed, Assets From Discontinued Operations Business Combinations, Recognized Identifiable Assets Acquired And Liabilities Consumed, Assets From Discontinued Operations Estimated fair value of total assets acquired Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Assets Acquired Including Goodwill Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Assets Acquired Including Goodwill Liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities [Abstract] Medical benefits payable Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Medical Benefits Payable Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Medical Benefits Payable Deferred tax liabilities, net Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities Other liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Liabilities Liabilities of discontinued operations Business Combinations, Recognized Identifiable Assets Acquired And Liabilities Consumed, Liabilities Of Discontinued Operations Business Combinations, Recognized Identifiable Assets Acquired And Liabilities Consumed, Discontinued Operations From Liabilities Estimated fair value of liabilities assumed Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities Estimated fair value of net assets acquired Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net Discontinued Operations and Disposal Groups [Abstract] Summary of Assets and Liabilities of Discontinued Operations Disposal Groups, Including Discontinued Operations [Table Text Block] Other than temporary impairment losses, investments Other than Temporary Impairment Losses, Investments MEDICAL BENEFITS PAYABLE [Abstract] Short-duration Insurance Contracts, Claims Development [Table] Short-duration Insurance Contracts, Claims Development [Table] Care1st Arizona Care1st Arizona [Member] Care1st Arizona [Member] Short-duration Insurance Contracts, Accident Year [Axis] Short-duration Insurance Contracts, Accident Year [Axis] Short-duration Insurance Contracts, Accident Year [Domain] Short-duration Insurance Contracts, Accident Year [Domain] 2016 Short-duration Insurance Contracts, Accident Year 2015 [Member] 2017 Short-duration Insurance Contracts, Accident Year 2016 [Member] Segments [Axis] Segments [Axis] Segments [Domain] Segments [Domain] Medicaid Health Plans Medicaid [Member] A reportable segment and business line which includes plans for beneficiaries of various Medicaid programs and state-based programs that are not a part of the Medicaid program. Medicare Health Plans Medicare Health Plans [Member] Medicare Health Plans Segment [Member] Medicare PDPs Prescription Drug Plans [Member] A reportable segment within the Medicare business line through which the entity offers Medicare Part D coverage to Medicare-eligible beneficiaries. Claims Development [Line Items] Claims Development [Line Items] Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net Total of IBNR Liabilities Plus Expected Development on Reported Claims Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net Cumulative Number of Reported Claims Short-duration Insurance Contracts, Number of Reported Claims Acquired medical benefits payable liabilities Liability for Unpaid Claims and Claims Adjustment Expense, Business Acquisitions Acquired reinsurance receivable Reinsurance Recoverable for Paid and Unpaid Claims and Claims Adjustments Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net All outstanding liabilities before 2016, net of reinsurance Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented Liabilities for unpaid claims and claim adjustment expenses, net of reinsurance Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net Purchase price Payments to Acquire Businesses, Gross Number of members acquired Number of Members Acquired Number of Members Acquired Tangible assets acquired Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Tangible Assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Tangible Assets Estimated fair value of liabilities assumed Identified intangible assets acquired Weighted average useful life Acquired Finite-lived Intangible Assets, Weighted Average Useful Life Schedule of Goodwill [Table] Schedule of Goodwill [Table] Medicare Health Plans Goodwill [Line Items] Goodwill [Line Items] Estimated useful life Finite-Lived Intangible Asset, Useful Life Impairment of intangible assets Impairment of Intangible Assets (Excluding Goodwill) Statement of Stockholders' Equity [Abstract] Statement [Table] Statement [Table] Statement, Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Common Stock Common Stock [Member] Paid in Capital Additional Paid-in Capital [Member] Retained Earnings Retained Earnings [Member] Accumulated Other Comprehensive Loss AOCI Attributable to Parent [Member] Statement [Line Items] Statement [Line Items] Increase (Decrease) in Stockholders' Equity Increase (Decrease) in Stockholders' Equity [Roll Forward] Balance, beginning of period (in shares) Common Stock, Shares, Outstanding Balance, beginning of period Stockholders' Equity Attributable to Parent Common stock issued for exercised stock options (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Common stock issued for exercised stock options Stock Issued During Period, Value, Stock Options Exercised Common stock issued for vested stock-based compensation awards (in shares) Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures Common stock issued for vested stock-based compensation awards Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures Repurchase and retirement of shares to satisfy tax withholding requirements (in shares) Stock Repurchased During Period, Shares Repurchase and retirement of shares to satisfy tax withholding requirements Stock Repurchased During Period, Value Stock-based compensation expense, net of forfeitures Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition Incremental tax benefit from stock-based compensation Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation Comprehensive income (loss) Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Balance, end of period (in shares) Balance, end of period Property, Plant and Equipment [Abstract] Summary of Property, Equipment and Capitalized Software Property, Plant and Equipment [Table Text Block] Goodwill and Intangible Assets Disclosure [Abstract] GOODWILL AND OTHER INTANGIBLE ASSETS, NET Goodwill and Intangible Assets Disclosure [Text Block] Medical Benefits Payable Schedule of Medical Benefits Payable [Table Text Block] Description and amounts of the components of medical benefits payable at the end of the reporting period. Reconciliation of the Beginning and Ending Balances of Medical Benefits Payable Reconciliation of Medical Benefits Payable [Table Text Block] A reconciliation of the beginning and ending balances of medical benefits payable, including separate disclosure of medical benefits incurred and medical benefits paid during the reporting period. Incurred and Paid Claims Development Information Short-duration Insurance Contracts, Claims Development [Table Text Block] Reconciliation of Net Incurred and Paid Claims Development to the Liability for Claims and Claim Adjustment Expenses Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Table Text Block] Segment [Domain] Goodwill, Impaired, Accumulated Impairment Loss Goodwill, Impaired, Accumulated Impairment Loss Goodwill [Roll Forward] Goodwill [Roll Forward] Beginning balance Acquired goodwill, preliminary allocation Goodwill, Acquired During Period Measurement period adjustments Goodwill, Purchase Accounting Adjustments Ending balance Subsequent recognition of deferred tax liability Retirement Benefits [Abstract] EMPLOYEE BENEFIT PLANS Pension and Other Postretirement Benefits Disclosure [Text Block] Fair Value Disclosures [Abstract] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Hierarchy [Axis] Fair Value, Hierarchy [Axis] Fair Value Hierarchy [Domain] Fair Value Hierarchy [Domain] Significant Unobservable Inputs (Level 3) Fair Value, Inputs, Level 3 [Member] Fair Value by Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Fair Value Measurements, Recurring Fair Value, Measurements, Recurring [Member] Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Domain] Major Types of Debt and Equity Securities [Domain] Auction Rate Securities Auction Rate Securities [Member] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Balance at beginning of period Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value Realized gains (losses) in earnings Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings Changes in net unrealized gains and losses in other comprehensive income Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss) Purchases, sales and redemptions Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases, (Sales), Issuances, (Settlements) Net transfers in or (out) of Level 3 Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net Balance at end of period Quarterly Financial Information Disclosure [Abstract] QUARTERLY FINANCIAL INFORMATION Quarterly Financial Information [Text Block] Document and Entity Information [Abstract] Document and Entity Information [Abstract] Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Well-known Seasoned Issuer Entity Well-known Seasoned Issuer Entity Voluntary Filers Entity Voluntary Filers Entity Current Reporting Status Entity Current Reporting Status Entity Filer Category Entity Filer Category Entity Public Float Entity Public Float Entity Common Stock, Shares Outstanding (in shares) Entity Common Stock, Shares Outstanding Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Document Type Document Type Amendment Flag Amendment Flag Document Period End Date Document Period End Date Restricted Investments Note [Abstract] RESTRICTED INVESTMENTS Restricted Assets Disclosure [Text Block] Summary of Restricted Cash and Investment Securities Restrictions on Cash and Cash Equivalents [Table Text Block] Schedule of Available-for-sale Securities [Table] Schedule of Available-for-sale Securities [Table] Asset-backed securities Asset-backed Securities [Member] Corporate debt securities Corporate Debt Securities [Member] Municipal securities Municipal Bonds [Member] Residential mortgage-backed securities Residential Mortgage Backed Securities [Member] Short-term time deposits Bank Time Deposits [Member] Government and agency obligations US Government Agencies Debt Securities [Member] Other securities Other Security Investments [Member] Schedule of Available-for-sale Securities [Line Items] Schedule of Available-for-sale Securities [Line Items] Amortized Cost Available-for-sale Securities, Amortized Cost Basis Gross Unrealized Gains Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax Gross Unrealized Losses Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax Estimated Fair Value Available-for-sale Securities Liability for Claims and Claims Adjustment Expense [Table] Liability for Claims and Claims Adjustment Expense [Table] Liability for Claims and Claims Adjustment Expense [Line Items] Liability for Claims and Claims Adjustment Expense [Line Items] Reinsurance Recoverable Total gross liability for unpaid claims and claim adjustment expense Liability for Claims and Claims Adjustment Expense REGULATORY CAPITAL AND DIVIDEND RESTRICTIONS [Abstract] Consolidated Entities [Axis] Consolidated Entities [Axis] Consolidated Entities [Domain] Consolidated Entities [Domain] Subsidiaries Subsidiaries [Member] Minimum capital and surplus requirement Statutory Accounting Practices, Statutory Capital and Surplus Required Combined statutory capital and surplus Statutory Accounting Practices, Statutory Capital and Surplus, Balance Dividends received from regulated subsidiaries Dividends received from regulated subsidiaries Dividends received from regulated subsidiaries during the current period. Dividends paid without regulatory approval Statutory Accounting Practices, Dividends Paid without Approval of Regulatory Agency Statutory Accounting Practices, Dividends Paid without Approval of Regulatory Agency Dividends paid with regulatory approval Statutory Accounting Practices, Dividends Paid with Approval of Regulatory Agency Amount of dividends that may be paid through the end of 2018 without prior approval by regulatory authorities Statutory Accounting Practices, Statutory Amount Available for Dividend Payments without Regulatory Approval Disposal Groups, Including Discontinued Operations [Table] Disposal Groups, Including Discontinued Operations [Table] Disposal Group Name [Axis] Disposal Group Name [Axis] Disposal Group Name [Domain] Disposal Group Name [Domain] Traditional Insurance Business Traditional Insurance Business [Member] Traditional Insurance Business [Member] Disposal Group Classification [Axis] Disposal Group Classification [Axis] Disposal Group Classification [Domain] Disposal Group Classification [Domain] Discontinued Operations, Held-for-sale Discontinued Operations, Held-for-sale [Member] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Life insurance subsidiaries disposed by sale Discontinued Operations, Subsidiaries Disposed by Sale Discontinued Operations, Subsidiaries Disposed by Sale Assets Disposal Group, Including Discontinued Operation, Assets [Abstract] Cash and cash equivalents Disposal Group, Including Discontinued Operation, Cash and Cash Equivalents Investments Disposal Group, Including Discontinued Operation, Investments Disposal Group, Including Discontinued Operation, Investments Reinsurance recoverables Disposal Group, Including Discontinued Operation, Reinsurance Recoverables Disposal Group, Including Discontinued Operation, Reinsurance Recoverables Other assets Disposal Group, Including Discontinued Operation, Other Assets Total Assets Disposal Group, Including Discontinued Operation, Assets Liabilities Disposal Group, Including Discontinued Operation, Liabilities [Abstract] Reserves and other policy liabilities Disposal Group, Including Discontinued Operation, Accrued Liabilities Other liabilities Disposal Group, Including Discontinued Operation, Other Liabilities Total liabilities Disposal Group, Including Discontinued Operation, Liabilities Net Receivables and Payables from Government Partners [Table] Net Receivables and Payables from Government Partners [Table] Net Receivables and Payables from Government Partners [Table] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Current Assets Current Assets [Member] Current Assets [Member] Current Liabilities Current Liabilities [Member] Current Liabilities [Member] 2016 Part D Plan 2016 Part D Plan [Member] 2016 Part D Plan [Member] Net Receivables and Payables from Government Partners [Line Items] Net Receivables and Payables from Government Partners [Line Items] [Line Items] for Net Receivables and Payables from Government Partners [Table] Allowance for uncollectible premiums receivable Premiums Receivable, Allowance for Doubtful Accounts Supplemental Medicaid premium revenue Premium revenue related to newborn and obstetric deliveries Premium revenue recognized during the period related to supplemental payments for newborns and/or obstetric deliveries under Medicaid contracts with state governments. Fee reimbursement Health Care Organization, Premium Revenue, Fee Reimbursement Health Care Organization, Premium Revenue, Fee Reimbursement Risk adjusted premiums receivable Risk Adjusted Premiums Risk Adjusted Premiums Variance above target amount before additional premiums are received Minimum variance above target amount before CMS makes additional payments to plan sponsors The minimum percentage variance above the target amount before Centers for Medicare and Medicaid Services makes additional payments to plan sponsors as part of the CMS corridor calculation. Minimum medical loss ratio Minimum Medical Loss Ratio Minimum Medical Loss Ratio "MLR" as determined under the Affordable Care Act "ACA." Insurance settlement period subsequent to plan year Insurance Settlements, Subsequent Payment Period Insurance Settlements, Subsequent Payment Period Drug costs reimbursed Drug Costs Reimbursed The percentage of drug costs reimbursed by CMS after a member reaches his or her out of pocket catastrophic threshold through a catastrophic reinsurance subsidy. Net payable for the benefit of members Funds (Payable) Receivable For The Benefit Of Members Funds (Payable) Receivable For The Benefit Of Members Net payable for the benefit of members, settlement period Funds (Payable) Receivable For The Benefit Of Members, Settlement Period Funds (Payable) Receivable For The Benefit Of Members, Settlement Period Total revenues Revenues Gross margin Gross Profit Income from operations Operating Income (Loss) Income before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Net income Net Income (Loss) Attributable to Parent Net income per share - basic (in dollars per share) Earnings Per Share, Basic Net income per share - diluted (in dollars per share) Earnings Per Share, Diluted Period end membership Membership Represents the number of members enrolled in the health care plan as of the end of the reporting period. Premium Revenue by Geographic Location Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas [Table Text Block] Financial Information by Reportable Operating Segments Schedule of Segment Reporting Information, by Segment [Table Text Block] Statement of Cash Flows [Abstract] Cash flows from operating activities: Net Cash Provided by (Used in) Operating Activities [Abstract] Net income Adjustments to reconcile net income to cash flows from operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation and amortization Depreciation, Depletion and Amortization, Nonproduction Loss on extinguishment of debt Gain (Loss) on Extinguishment of Debt Stock-based compensation expense Share-based Compensation Deferred taxes, net Deferred Income Tax Expense (Benefit) Other, net Other Operating Activities, Cash Flow Statement Changes in operating accounts, net of effects from acquisitions and divestitures: Increase (Decrease) in Operating Capital [Abstract] Premiums receivable, net Increase (Decrease) in Premiums Receivable Pharmacy rebates receivable, net Increase (Decrease) in Other Receivables Medical benefits payable Increase (Decrease) in Health Care Insurance Liabilities Unearned premiums Increase (Decrease) in Unearned Premiums Other receivables/payables to government partners Increase Decrease In Other Payables To Government Partners The net change during the reporting period in amounts due to government agencies under various contractual and plan arrangements. We estimate the amounts due from CMS for risk protection under the risk corridor provisions of our contract with CMS each period based on pharmacy claims experience. Amount payable related to investigation resolution Increase Decrease In Amounts Accrued Related To Investigation Resolution Net Amounts accrued related to the investigation resolution represents the current status of all matters and information known to us to date and is management's best estimate of the long-term liability associated with the matters remaining under investigation. Accrued liabilities and other, net Increase (Decrease) in Accrued Liabilities and Other Operating Liabilities Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities Cash flows from investing activities: Net Cash Provided by (Used in) Investing Activities [Abstract] Acquisitions and acquisition-related settlements, net of cash acquired Payments to Acquire Businesses, Net of Cash Acquired Purchases of investments Payments to Acquire Investments Proceeds from sales and maturities of investments Proceeds from Sale, Maturity and Collection of Investments Additions to property, equipment and capitalized software, net Payments to Acquire Productive Assets Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities Cash flows from financing activities: Net Cash Provided by (Used in) Financing Activities [Abstract] Proceeds from debt, net of financing costs paid Proceeds from Issuance of Long-term Debt Payments on debt Repayments of Short-term Debt Repurchase and retirement of shares to satisfy tax withholding requirements Payments Related to Tax Withholding for Share-based Compensation Funds received for the benefit of members, net Proceeds from (Payments for) the Benefit of Members Proceeds from (Payments for) the Benefit of Members Other, net Proceeds from (Payments for) Other Financing Activities Net cash provided by (used in) financing activities Net Cash Provided by (Used in) Financing Activities Increase (decrease) in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Balance at beginning of period Cash and Cash Equivalents, at Carrying Value Balance at end of period SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION: Supplemental Cash Flow Information [Abstract] Cash paid for taxes Income Taxes Paid, Net Cash paid for interest Interest Paid, Net SUPPLEMENTAL DISCLOSURES OF NON-CASH TRANSACTIONS: Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Non-cash additions to property, equipment, and capitalized software Capital Expenditures Incurred but Not yet Paid Income Tax Disclosure [Abstract] Reconciliation of income tax at the effective rate to income tax at the statutory federal rate Effective Income Tax Rate Reconciliation, Amount [Abstract] Income tax expense at statutory federal rate Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount Adjustments resulting from: Increase (reduction) resulting from [Abstract] State income tax, net of federal benefit Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount Unrecognized tax benefits Effective Income Tax Rate Reconciliation, Nondeductible Expense, Executive Compensation The portion of the difference between total income tax expense or benefit as reported in the Income Statement for the period and the expected income tax expense or benefit computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations attributable to non-deductible executive compensation. Tax rate change Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount Non-deductible ACA industry fees Effective Income Tax Rate Reconciliation, Nondeductible Expense, Other, Amount Other, net Effective Income Tax Rate Reconciliation, Other Reconciling Items, Amount Total income tax expense Income Tax Expense (Benefit) Assets and Liabilities Measured at Fair Value Fair Value, Assets Measured on Recurring Basis [Table Text Block] Changes in Fair Value of Level 3 Investments Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Carrying Value and Fair Value of Long-term Debt Schedule of Carrying Values and Estimated Fair Values of Debt Instruments [Table Text Block] Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Use of Estimates Use of Estimates, Policy [Policy Text Block] Reclassifications Reclassification, Policy [Policy Text Block] Recently Adopted and Issued Accounting Standards New Accounting Pronouncements, Policy [Policy Text Block] Premium Revenue Recognition and Premiums Receivable Revenue Recognition, Policy [Policy Text Block] Minimum Medical Expense and Risk Corridor Provisions Other payables to government partners [Policy Text Block] Disclosure of accounting policy for the amounts due to government agencies under various contractual and plan arrangements. Medicare Part D Settlements Funds receivable held for benefit of members [Policy Text Block] Disclosure of accounting policy for government payments received or to be received to subsidize the member portion of medical payments for certain of the company's stand-alone prescription drug program members. Medical Benefits Expense and Medical Benefits Payable Medical benefits payable and expense [Policy Text Block] Disclosure of accounting policy for medical benefits payable and expense. ACA Industry Fee ACA Industry Fee [Policy Text Block] ACA Industry Fee [Policy Text Block] Equity-Based Employee Compensation Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block] Medicaid Premium Taxes Medicaid premium taxes [Policy Text Block] Disclosure of accounting policy for Medicaid premium taxes. Income Tax Expense Income Tax, Policy [Policy Text Block] Cash and Cash Equivalents Cash and Cash Equivalents, Policy [Policy Text Block] Investments Investment, Policy [Policy Text Block] Restricted Investments Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block] Prepaid Expenses and Other Current Assets Prepaid expenses and other current assets, net [Policy Text Block] Disclosure of accounting policy for the total of the amounts paid in advance for capitalized costs that will be expensed with the passage of time or the occurrence of a triggering event, and will be charged against earnings within one year or the normal operating cycle, if longer, and the aggregate carrying amount of current assets, as of the balance sheet date, not separately presented elsewhere in the balance sheet. Property, Equipment and Capitalized Software, net Property, Plant and Equipment, Policy [Policy Text Block] Goodwill and Other Intangible Assets Goodwill and Intangible Assets, Policy [Policy Text Block] Accounts Payable and Accrued Expenses Accounts Payable and Accrued Expenses [Policy Text Block] Accounts Payable and Accrued Expenses [Policy Text Block] Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Quoted Prices in Active Markets for Identical Assets (Level 1) Fair Value, Inputs, Level 1 [Member] Significant Other Observable Inputs (Level 2) Fair Value, Inputs, Level 2 [Member] Measurement Basis [Axis] Measurement Basis [Axis] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Portion at Fair Value Measurement [Member] Portion at Fair Value Measurement [Member] Carrying Value Reported Value Measurement [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Long-term debt outstanding Long-term Debt, Fair Value Condensed Financial Information of Parent Company Only Disclosure [Abstract] Schedule of Condensed Financial Statements [Table] Condensed Financial Statements [Table] Parent Company Parent Company [Member] Condensed Financial Statements, Captions [Line Items] Condensed Financial Statements, Captions [Line Items] Revenues: Revenues [Abstract] Investment and other income Investment And Other Income Investment income represents income derived from bank deposits and investments in securities consisting of interest income from cash instruments and securities, dividend income, and income or expense derived from the amortization of investment related discounts or premiums, respectively. Total revenues Expenses: Cost of Revenue [Abstract] Selling, general and administrative Selling, General and Administrative Expense Interest expense Interest Expense Total expenses, net Operating Expenses Income (loss) from operations Income before income taxes and equity in earnings of unconsolidated subsidiaries Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest Income before income taxes Income tax benefit Loss before equity in subsidiaries Net Income (Loss) before Net Income (Loss) from Subsidiaries Net Income (Loss) before Net Income (Loss) from Subsidiaries Equity in earnings of subsidiaries Income (Loss) from Subsidiaries, Net of Tax Net income Other comprehensive (loss) income, before tax: Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract] Change in net unrealized gains and losses on available-for-sale securities Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, before Tax Income tax (benefit) expense related to other comprehensive income Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax Other comprehensive income (loss), net of tax Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Comprehensive income Comprehensive Income (Loss), Net of Tax, Attributable to Parent PROPERTY, EQUIPMENT AND CAPITALIZED SOFTWARE Property, Plant and Equipment Disclosure [Text Block] Statement of Comprehensive Income [Abstract] Premium Premiums Earned, Net Expenses and other: Medical benefits Policyholder Benefits and Claims Incurred, Net, Health ACA industry fee ACA Industry Fee Expense ACA Industry Fee Expense Medicaid premium taxes Premium Tax Expense An assessment levied by a state government agency on premium revenue. Interest Gain on divestiture of business Gain (Loss) on Disposition of Business Equity in earnings of unconsolidated subsidiaries Income (Loss) from Equity Method Investments Income tax expense Other comprehensive income, before tax: Income tax benefit related to other comprehensive income (loss) Earnings per common share: Basic (in dollars per share) Diluted (in dollars per share) Weighted average common shares outstanding: Weighted Average Number of Shares Outstanding, Diluted [Abstract] Basic (in shares) Diluted (in shares) Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Geographical [Axis] Geographical [Axis] Geographical [Domain] Geographical [Domain] Kentucky KENTUCKY Florida FLORIDA Georgia GEORGIA Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Premium revenue as a percentage of consolidated premium revenue Premium Revenue, Net Of Premium Tax Represents premium revenue net of premium tax of consolidated premium revenue. Number of members Number Of Members Represents the number of members under the government-sponsored health care programs. MEDICAL BENEFITS PAYABLE Insurance Disclosure [Text Block] Components of Income Tax Expense Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Reconciliation of Income Tax Statutory Rate to Effective Rate Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Significant Components of Deferred Tax Assets and Liabilities Schedule of Deferred Tax Assets and Liabilities [Table Text Block] Reconciliation of Beginning and Ending Unrecognized Tax Benefits Summary of Income Tax Contingencies [Table Text Block] Premium deficiency reserve Provision for Loss on Contracts Organization, Consolidation and Presentation of Financial Statements [Abstract] Number of members served Number of states offered Medicare prescription drug plans Number of States in which Entity Operates Number of transactions for acquisition Business Acquisitions, Number of Transactions Business Acquisitions, Number of Transactions Commitments and Contingencies Disclosure [Abstract] Rental expense Operating Leases, Rent Expense Minimum Lease Payments Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract] 2018 Operating Leases, Future Minimum Payments Due, Next Twelve Months 2019 Operating Leases, Future Minimum Payments, Due in Two Years 2020 Operating Leases, Future Minimum Payments, Due in Three Years 2021 Operating Leases, Future Minimum Payments, Due in Four Years 2022 Operating Leases, Future Minimum Payments, Due in Five Years 2023 and thereafter Operating Leases, Future Minimum Payments, Due Thereafter Total Operating Leases, Future Minimum Payments Due Fair Value of Consideration Transferred in Acquisition Schedule of Business Acquisitions, by Acquisition [Table Text Block] Fair Value of Assets Acquired and Liabilities Assumed Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block] Preliminary Fair Values and Weighted Average Useful Lives for Identifiable Intangible Assets Acquired for Identifiable Intangible Assets Schedule of Finite-Lived Intangible Assets Acquired as Part of Business Combination [Table Text Block] Unaudited Pro Forma Results Business Acquisition, Pro Forma Information [Table Text Block] REGULATORY CAPITAL AND DIVIDEND RESTRICTIONS Statutory Capital And Dividend Restrictions [Text Block] This element may be used to capture the complete disclosure for insurance companies for regulatory capital requirements imposed by state insurance regulatory agencies. In addition, it discloses how the entity's reporting under GAAP as of the balance sheet date differs from the results based on prescribed and permitted accounting practices of the state or country of domicile in which a relevant statutory filing is made, or differences in results based on the National Association of Insurance Commissioners (NAIC) prescribed practices. Matching contribution expense Defined Contribution Plan, Cost COMMITMENTS AND CONTINGENCIES Commitments and Contingencies Disclosure [Text Block] Restrictions on Cash and Cash Equivalents [Table] Restrictions on Cash and Cash Equivalents [Table] Restricted Cash and Cash Equivalents, Cash and Cash Equivalents [Axis] Restricted Cash and Cash Equivalents [Axis] Restricted Cash and Cash Equivalents, Cash and Cash Equivalents [Domain] Cash and Cash Equivalents [Domain] Cash Cash [Member] Money market funds Money Market Funds [Member] U.S. government securities and other US Treasury and Government [Member] Restricted Cash and Cash Equivalents Items [Line Items] Restricted Cash and Cash Equivalents Items [Line Items] Restricted Investments Restricted Cash and Investments [Abstract] Amortized Cost Restricted Investments, Amortized Cost Basis Restricted Investments, Amortized Cost Basis Gross Unrealized Gains Restricted Investments, Gross Unrealized Gain, Before Tax Restricted Investments, Gross Unrealized Gain, Before Tax Gross Unrealized Losses Restricted Investments, Gross Unrealized Losses, Before Tax Restricted Investments, Gross Unrealized Losses, Before Tax Estimated Fair Value Restricted Cash and Cash Equivalents, Noncurrent Realized gains (losses) Restricted Investments, Realized Gains (Losses) Restricted Investments, Realized Gains (Losses) Disclosure of Compensation Related Costs, Share-based Payments [Abstract] Equity Award Performance Stock Units Stock-based compensation expense Common stock price (in dollars per share) Share Price Unrecognized compensation cost Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized Weighted-average period over which compensation costs are expected to be recognized Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition Weighted-average grant-date fair value of shares granted (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Total fair value of shares vested Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Asset Class [Axis] Asset Class [Axis] Asset Class [Domain] Asset Class [Domain] Credit Facility [Axis] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] Revolving Credit Facility Revolving Credit Facility [Member] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Auction rate securities, par value Borrowings outstanding Long-term Line of Credit, Noncurrent Depreciation expense Depreciation Depreciation expense on capitalized software Capitalized Computer Software, Amortization Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Letter of Credit Letter of Credit [Member] Term Loan Term Loan [Member] Term Loan [Member] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] ABR Loans ABR Loans [Member] ABR Loans [Member] Eurodollar Eurodollar [Member] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] 2016 Revolving Credit Facility 2016 Revolving Credit Facility [Member] 2016 Revolving Credit Facility [Member] Variable Rate [Axis] Variable Rate [Axis] Variable Rate [Domain] Variable Rate [Domain] Federal Reserve Bank of New York Rate Federal Reserve Bank of New York Rate [Member] Federal Reserve Bank of New York Rate [Member] London Interbank Offered Rate (LIBOR) London Interbank Offered Rate (LIBOR) [Member] Concentration Risk Type [Axis] Concentration Risk Type [Axis] Concentration Risk Type [Domain] Concentration Risk Type [Domain] Lender Concentration Risk Lender Concentration Risk [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Maximum borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Repayments of debt Repayments of Debt Borrowing capacity available for letters of credit Line of Credit Facility, Capacity Available for Trade Purchases Unutilized commitment fee percentage Line of Credit Facility, Unused Capacity, Commitment Fee Percentage Basis spread on variable rate Debt Instrument, Basis Spread on Variable Rate Minimum lender holding for accelerated maturity rights Debt Instrument, Covenant Terms, Default Provisions, Qualifying Lender, Minimum Percentage of Loans Held under Debt Agreement Debt Instrument, Covenant Terms, Default Provisions, Qualifying Lender, Minimum Percentage of Loans Held under Debt Agreement Favorable development of medical benefits payable Prior Year Claims and Claims Adjustment Expense Favorable development of medical benefits payable excluding the release of the provision for moderately adverse conditions Net Favorable (Unfavorable) Development of Medical Benefits Payable, Excluding Release of the Provision for Moderately Adverse Conditions Net Favorable (Unfavorable) Development of Medical Benefits Payable, Excluding Release of the Provision for Moderately Adverse Conditions Calculated Weighted-Average Common Shares Outstanding Schedule of Weighted Average Number of Shares [Table Text Block] IBNR Liability for Unpaid Claims and Claims Adjustment Expense, Incurred but Not Reported (IBNR) Claims, Amount Other medical benefits payable Liability for Unpaid Claims and Claims Adjustment Expense, Reported Claims, Amount Total medical benefits payable IBNR, percentage IBNR, Percentage Percentage of incurred but not reported (IBNR) estimated claims payable over total medical benefits payable during the period. Other medical benefits payable, percentage Claims adjudicated, but not yet paid, Percentage Percentage of claims adjudicated, but not yet paid, over total medical payable during the period. Total medical benefits payable, percentage Total Medical Benefits As A Percent of Total Medical Benefits Total Medical Benefits as a Percent of Total Medical Benefits STOCK-BASED COMPENSATION Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Schedule of Related Party Transactions, by Related Party [Table] Schedule of Related Party Transactions, by Related Party [Table] Related Party Transactions, by Related Party [Axis] Related Party [Axis] Related Party [Domain] Related Party [Domain] The Graham Companies The Graham Companies [Member] A related party from which the entity leases office space and in which a member of the entity's Board of Directors holds a significant interest, including interests held by immediate family members. Related Party Transaction [Line Items] Related Party Transaction [Line Items] Rental expenses, related parties Related Party Transaction, Expenses from Transactions with Related Party Selected Unaudited Quarterly Financial Data Quarterly Financial Information [Table Text Block] DISCONTINUED OPERATIONS Disposal Groups, Including Discontinued Operations, Disclosure [Text Block] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Senior Notes Senior Notes [Member] 4.00% Convertible Senior Notes 4.00% Convertible Senior Notes [Member] 4.00% Convertible Senior Notes [Member] Stock Compensation Plan Stock Compensation Plan [Member] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Preferred Stock Preferred Stock [Member] Business Combination, Consideration Transferred [Abstract] Business Combination, Consideration Transferred [Abstract] Cash consideration transferred Assumed debt Business Combination, Consideration Transferred, Liabilities Incurred Equity interests issued Business Combination, Consideration Transferred, Equity Interests Issued and Issuable Total consideration transferred Business Combination, Consideration Transferred Common stock, outstanding (in shares) Interest rate Debt Instrument, Interest Rate, Stated Percentage Payments for repurchase of preferred shares (in shares) Payments for Repurchase of Redeemable Preferred Stock Payments for repurchase of preferred shares and accrued dividends Payments for Repurchase of Redeemable Preferred Stock, Including Ordinary Dividends Payments for Repurchase of Redeemable Preferred Stock, Including Ordinary Dividends Payments of accrued dividends Payments of Ordinary Dividends, Preferred Stock and Preference Stock Unrecognized stock compensation cost Acquisition Related Compensation Cost Acquisition Related Compensation Cost Statement of Financial Position [Abstract] Assets Assets [Abstract] Current Assets: Assets, Current [Abstract] Cash and cash equivalents Short-term investments Short-term Investments Premiums receivable, net Premiums Receivable, Net Pharmacy rebates receivable, net Other Receivables, Net, Current Receivables from government partners Receivables from government partners Receivables from government partners Funds receivable for the benefit of members Funds Receivable For The Benefit Of Members Funds held or receivable for the benefit of members represent government payments received or to be received to subsidize the member portion of medical payments for certain of our stand-alone prescription drug program members. We do not bear underwriting risk since such funds represent pass-through payments from our government partners to fund deductibles, co-payments and other participant benefits. Prepaid expenses and other current assets, net Prepaid Expense and Other Assets, Current Total current assets Assets, Current Property, equipment and capitalized software, net Property, Plant and Equipment, Net Other intangible assets, net Intangible Assets, Net (Excluding Goodwill) Long-term investments Long-term Investments Restricted investments Other assets Other Assets, Noncurrent Assets of discontinued operations Disposal Group, Including Discontinued Operation, Assets, Noncurrent Total Assets Assets Liabilities and Stockholders' Equity Liabilities and Equity [Abstract] Current Liabilities: Liabilities, Current [Abstract] Medical benefits payable Unearned premiums Unearned Premiums Accounts payable and accrued expenses Accounts Payable and Other Accrued Liabilities, Current Funds payable for the benefit of members Funds Payable For The Benefit of Members Funds held (payable) or receivable for the benefit of members represent government payments received or to be received to subsidize the member portion of medical payments for certain of our stand-alone prescription drug program members. We do not bear underwriting risk since such funds represent pass-through payments from our government partners to fund deductibles, co-payments and other participant benefits. Other payables to government partners Other Payables To Government Partners Other payables due to government partners represent amounts due to government agencies under various contractual and plan arrangements. We estimate the amounts due to CMS for risk protection under the risk corridor provisions of our contract with CMS each period based on pharmacy claims experience. Also this line item includes reserves for the return of premium on minimum loss ratio guarantees for certain state Medicaid contracts. Total current liabilities Liabilities, Current Deferred income tax liability Deferred Income Tax Liabilities, Net Long-term debt, net Long-term Debt, Excluding Current Maturities Other liabilities Other Liabilities, Noncurrent Liabilities of discontinued operations Disposal Group, Including Discontinued Operation, Liabilities, Noncurrent Total Liabilities Liabilities Commitments and contingencies Commitments and Contingencies Stockholders' Equity: Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Preferred stock, $0.01 par value (20,000,000 authorized, no shares issued or outstanding) Preferred Stock, Value, Issued Common stock, $0.01 par value (100,000,000 authorized, 44,522,988 and 44,293,881 shares issued and outstanding at December 31, 2017 and December 31, 2016, respectively) Common Stock, Value, Issued Paid-in capital Additional Paid in Capital Retained earnings Retained Earnings (Accumulated Deficit) Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Total Stockholders' Equity Total Liabilities and Stockholders' Equity Liabilities and Equity Preferred stock, par value (in dollars per share) Preferred Stock, Par or Stated Value Per Share Preferred stock, authorized (in shares) Preferred Stock, Shares Authorized Preferred stock, issued (in shares) Preferred Stock, Shares Issued Preferred stock, outstanding (in shares) Preferred Stock, Shares Outstanding Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Common stock, authorized (in shares) Common Stock, Shares Authorized Common stock, issued (in shares) Common Stock, Shares, Issued Common stock, outstanding (in shares) SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Significant Accounting Policies [Text Block] Phoenix Health Plan Phoenix Health Plan [Member] Phoenix Health Plan [Member] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Membership Customer-Related Intangible Assets [Member] Tradenames Trade Names [Member] Provider networks Provider Network [Member] Provider networks are lists of physicians and hospitals that provide services to a health insurance plan. Other Other Intangible Assets [Member] Gross fair value Finite-lived Intangible Assets Acquired Assets Cash and cash equivalents Taxes receivable Income Taxes Receivable Affiliate receivables and other current assets Affiliate receivables and other current assets The aggregate amount of receivables to be collected from related parties where one party can exercise control or significant influence over another party; including affiliates, owners or officers and their immediate families, pension trusts, and so forth, at the financial statement date. which are usually due within one year (or one business cycle), along with other current assets. Deferred tax asset Deferred Income Tax Assets, Net Investment in subsidiaries Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures Liabilities and Stockholders' Equity Accrued expenses and other current liabilities Accrued Liabilities and Other Liabilities Long-term debt Preferred stock, $0.01 par value (20,000,000 authorized, no shares issued or outstanding) Common stock, $0.01 par value (100,000,000 authorized, 44,522,988 and 44,293,881 shares issued and outstanding at December 31, 2017 and December 31, 2016, respectively) Current: Current Income Tax Expense (Benefit), Continuing Operations [Abstract] Federal Current Federal Tax Expense (Benefit) State Current State and Local Tax Expense (Benefit) Total current Current Income Tax Expense (Benefit) Deferred: Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract] Federal Deferred Federal Income Tax Expense (Benefit) State Deferred State and Local Income Tax Expense (Benefit) Total deferred Deferred Other Tax Expense (Benefit) Schedule of Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Property, Plant and Equipment by Type [Axis] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Domain] Property, Plant and Equipment, Type [Domain] Leasehold improvements Leasehold Improvements [Member] Computer equipment Computer Equipment [Member] Capitalized software Software and Software Development Costs [Member] Furniture and equipment Furniture and Equipment [Member] Long lived, depreciable assets, commonly used in offices and stores and tangible personal property, nonconsumable in nature, with finite lives used to produce goods and services. Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Property, equipment and capitalized software, gross Property, Plant and Equipment, Gross Less accumulated depreciation Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Total property and equipment, net Deferred tax assets Deferred Tax Assets, Gross [Abstract] Net operating losses Deferred Tax Assets, Operating Loss Carryforwards Foreign tax credits Deferred Tax Assets, Tax Credit Carryforwards, Foreign Medical and other benefits discounting Deferred Tax Assets, Medical and other benefits discounting The tax effect as of the balance sheet date of the amount of the estimated future tax deductions arising from unrealized losses on medical and other benefits discounting which can only be deducted for tax purposes when the losses are realized, and which can only be realized if sufficient tax-basis income is generated in future periods to enable the deduction to be taken. Medical and other benefits discounting Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Allowance for Doubtful Accounts Allowance for doubtful accounts Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-based Compensation Cost Unearned premium discounting Deferred Tax Assets, Unearned Premium Discounting Deferred Tax Assets, Unearned Premium Discounting Capital losses Deferred Tax Assets, Capital Loss Carryforwards Premium deficiency reserve Deferred Tax Assets, Premium Deficiency Reserve Deferred Tax Assets, Premium Deficiency Reserve Accrued expenses and other Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Other Total deferred tax assets Deferred Tax Assets, Gross Valuation allowance Deferred Tax Assets, Valuation Allowance Total deferred tax assets Deferred Tax Assets, Net of Valuation Allowance Deferred tax liabilities Deferred Tax Liabilities, Gross [Abstract] Goodwill and other intangible assets Deferred Tax Liabilities, Goodwill and Intangible Assets Software development costs and property and equipment Deferred Tax Liabilities, Deferred Expense, Capitalized Software Prepaid assets Deferred Tax Liabilities, Prepaid assets The amount as of the balance sheet date of the estimated future tax effects attributable to the difference between the methods used to account for prepaid assets for tax purposes and under generally accepted accounting principles. Total deferred tax liabilities Deferred Tax Liabilities, Gross Net deferred tax liability Deferred Tax Liabilities, Net Performance Stock Units Performance Share Awards [Member] Performance share awards to a former executive of the company as a form of incentive compensation. Summary of Activity for RSU Awards Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity [Table Text Block] Summary of Activity for Nonvested Awards Schedule of Nonvested Performance-based Units Activity [Table Text Block] Schedule I - CONDENSED FINANCIAL INFORMATION OF REGISTRANT Condensed Financial Information of Parent Company Only Disclosure [Text Block] DEBT Debt Disclosure [Text Block] Equity Instruments Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Outstanding at beginning of period (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Vested (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Forfeited and expired (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Outstanding at end of period (in shares) Weighted Average Grant-Date Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Outstanding as of beginning of period (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Granted (in dollars per share) Vested (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Forfeited and expired (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Outstanding at end of period (in dollars per share) 5.25% Senior Notes, due April 1, 2025 5.25 Percent Senior Notes Due 2025, Issued 2017 [Member] 5.25 Percent Senior Notes Due 2025, Issued 2017 [Member] 5.75% Senior Notes, due November 15, 2020 5.75 Percent Senior Notes Due 2020, Issued 2015 [Member] 5.75 Percent Senior Notes Due 2020, Issued 2015 [Member] 5.75% Senior Notes due 2020 Senior Notes Due 2020 [Member] Senior Notes Due 2020 Debt Instrument, Redemption, Period [Axis] Debt Instrument, Redemption, Period [Axis] Debt Instrument, Redemption, Period [Domain] Debt Instrument, Redemption, Period [Domain] 2016 Debt Instrument, Redemption, Period One [Member] Aggregate principal amount Debt Instrument, Face Amount Aggregate net proceeds from the issuance of debt Proceeds from Issuance of Debt Debt repurchase amount Debt Instrument, Repurchase Amount Minimum additional indebtedness pursuant to the fixed charge coverage ratio Debt Instrument, Covenant, Restructuring Restrictions, Minimum Additional Borrowing Capacity Pursuant To Fixed Charge Coverage Ratio Debt Instrument, Covenant, Restructuring Restrictions, Minimum Additional Borrowing Capacity Pursuant To Fixed Charge Coverage Ratio Percentage of principal amount redeemed Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed Redemption price Debt Instrument, Redemption Price, Percentage Percentage of principal amount outstanding Debt Instrument, Redemption Price, Required Percentage Of Principal Amount Outstanding Debt Instrument, Redemption Price, Required Percentage Of Principal Amount Outstanding Days within closing of equity offering Debt Instrument, Early Redemption Condition, Maximum Days Within Closing Equity Offering Debt Instrument, Early Redemption Condition, Maximum Days Within Closing Equity Offering Redemption premium, percentage of principal amount redeemed Debt Instrument, Redemption Premium, Percentage of Principal Amount Redeemed Debt Instrument, Redemption Premium, Percentage of Principal Amount Redeemed Issue price Debt Instrument, Issue Price, Percentage Debt Instrument, Issue Price, Percentage Unamortized debt premium Debt Instrument, Unamortized Premium Total available-for-sale investments sold Proceeds from Sale of Available-for-sale Securities, Debt Realized gains and losses Available-for-sale Securities, Gross Realized Gain (Loss) Other than temporary impairment losses Other than Temporary Impairment Losses, Investments, Available-for-sale Securities Managed Medical Assistance Program (MMA) Managed Medical Assistance Program [Member] Managed Medical Assistance Program Number of renewal options Number Of Renewal Options The number of times a contract may optionally be renewed after the expiration of the initial contract term. Health plan contract, renewal term Health Plan Contract, Renewal Term Health Plan Contract, Renewal Term Number of regions executed contracts Number Of Regions Executed Contracts Number of Regions executed contracts during the period Total number of regions Total Number Of Regions Total number of regions Number of reportable segments Number of Reportable Segments Reconciliation of the beginning and ending amount of unrecognized tax benefits Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] Unrecognized tax benefits, beginning of period Unrecognized Tax Benefits Increases: Gross increases [Abstract] Prior year tax positions Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions Current year tax positions Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions Decreases: Gross decreases [Abstract] Prior year tax positions Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions Unrecognized tax benefits, end of period PHP, Universal American, Care 1st Arizona, Advicare Corp. PHP, Universal American, Care 1st Arizona, Advicare Corp. [Member] PHP, Universal American, Care 1st Arizona, Advicare Corp. [Member] Total revenues Business Acquisition, Pro Forma Revenue Net income Business Acquisition, Pro Forma Net Income (Loss) Earnings per common share Basic (in dollars per share) Business Acquisition, Pro Forma Earnings Per Share, Basic Diluted (in dollars per share) Business Acquisition, Pro Forma Earnings Per Share, Diluted Total Within 1 Year Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value 1 Through 5 Years Available-for-sale Securities, Debt Maturities, Year Two Through Five, Fair Value 5 Through 10 Years Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Fair Value Thereafter Available-for-sale Securities, Debt Maturities, after Ten Years, Fair Value Future Minimum Lease Payments Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block] EARNINGS PER COMMON SHARE Earnings Per Share [Text Block] FAIR VALUE MEASUREMENTS Fair Value Disclosures [Text Block] Loss Contingencies [Table] Loss Contingencies [Table] Loss Contingencies by Nature of Contingency [Axis] Loss Contingency Nature [Axis] Loss Contingency, Nature [Domain] Loss Contingency, Nature [Domain] Derivative Lawsuits Derivative Lawsuits [Member] A lawsuit brought by a corporation shareholder against the directors, management and/or other shareholders of the corporation, for a failure by management. United States Securities And Exchange Commission United States Securities And Exchange Commission [Member] United States Securities And Exchange Commission [Member] Litigation Case [Axis] Litigation Case [Axis] Litigation Case [Domain] Litigation Case [Domain] Mr. Farha Case Mr. Farha Case [Member] Mr. Farha Case [Member] Mr. Behrens Case Mr. Behrens Case [Member] Mr. Behrens Case [Member] Mr. Bereday Case Mr. Bereday Case [Member] Mr. Bereday Case Loss Contingencies [Line Items] Loss Contingencies [Line Items] Number of former officers being pursued in an action filed by the entity Number Of Former Officers Being Pursued In Action Filed By Entity The number of former officers being pursued in an action filed by the entity pursuant to a report filed by the Special Litigation Committee to the Federal Court determining, among other things, that the entity should pursue such an action. Number of former associates being pursued in action filed by entity Number Of Former Associates Being Pursued In Action Filed By Entity Number Of Former Associates Being Pursued In Action Filed By Entity Number of former employees found guilty Number Of Former Employees Found Guilty and Appealing Number Of Former Employees Found Guilty and Appealing Number of former employees receiving notices of cross appeal Number Of Former Employees Receiving Notices of Cross Appeal Number Of Former Employees Receiving Notices of Cross Appeal Number of former employees being pursued in action filed by entity Number Of Former Employees Being Pursued In Action Filed By Entity Number Of Former Employees Being Pursued In Action Filed By Entity Number of actions filed in the federal and state courts between October 2007 and January 2008 Number of actions filed in the Federal Court The number of actions filed in Federal Court related to government investigations in a derivative action filed against the entity. Settlement payment received Litigation Settlement, Amount Awarded from Other Party Maximum legal fee obligation Litigation Settlement, Legal Fee Advances, Maximum Litigation Settlement, Legal Fee Advances, Maximum Legal fees Legal Fees Statutory federal income tax rate Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent Effective income tax rate Effective Income Tax Rate Reconciliation, Percent One-time, non-cash decrease to income tax expense Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Provisional Income Tax Expense (Benefit) Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Provisional Income Tax Expense (Benefit) Effective tax rate as a result of the Tax Cuts and Jobs Act 2017 Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Percent Valuation allowance adjustments resulting from the Tax Cuts and Jobs Act of 2017 Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Change in Tax Rate, Deferred Tax Asset, Provisional Income Tax Expense (Benefit) Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Change in Tax Rate, Deferred Tax Asset, Provisional Income Tax Expense (Benefit) Previously unrecognized tax benefits recognized Previously unrecognized tax benefits recognized, tax settlement Unrecognized Tax Benefits, Period Increase (Decrease) Amortization expense Amortization of Intangible Assets Expected Amortization Expense Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract] 2018 Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months 2019 Finite-Lived Intangible Assets, Amortization Expense, Year Two 2020 Finite-Lived Intangible Assets, Amortization Expense, Year Three 2021 Finite-Lived Intangible Assets, Amortization Expense, Year Four 2022 Finite-Lived Intangible Assets, Amortization Expense, Year Five 2023 and thereafter Finite-Lived Intangible Assets, Amortization Expense, after Year Five Total Finite-Lived Intangible Assets, Net Low-income cost sharing subsidy Funds Receivable For Benefit Of Members Low Income Cost Sharing Subsidy Amount of low-income cost sharing subsidy for qualifying low income status members that the Center for Medicare and Medicaid Services ("CMS") reimburses for all or a portion of the member's deductible, coinsurance and co-payment amounts above the out of pocket threshold for low income beneficiaries. Low-income cost sharing subsidies are paid by CMS prospectively as a fixed amount per member per month, and are determined based upon the plan year bid the entity submitted to CMS. Catastrophic reinsurance subsidy Funds Receivable For Benefit Of Members Catastrophic Reinsurance Subsidy Amount of catastrophic reinsurance subsidy paid by Center for Medicare and Medicaid Services ("CMS") prospectively as a fixed amount per member per month, and determined based upon the plan year bid we submitted to CMS. CMS reimburses for 80% of the drug costs after a member reaches his or her out of pocket catastrophic threshold through a catastrophic reinsurance subsidy. Coverage gap discount subsidy Funds Receivable For Benefit Of Members Coverage Gap Discount Subsidy Amount of coverage gap discount subsidy for monthly prospective payments by Center for Medicare and Medicaid Services ("CMS") for pharmaceutical manufacturer discounts made available to members. The prospective discount payments are determined based upon the plan year bid submitted by plan sponsors to CMS and current plan enrollment. Funds payable for the benefit of members Long-term debt, net Long-term Debt, Excluding Current Maturities [Abstract] Senior notes, noncurrent Senior Notes, Noncurrent Revolving Credit Facility Debt issuance costs Debt Issuance Costs, Noncurrent, Net Total long-term debt, net Net cash (used in) provided by operating activities Cash used in investing activities: Net proceeds (payments) from purchases and sales and maturities of investments Payments for (Proceeds from) Investments Payments to subsidiaries, net Capital contributions to subsidiaries The cash outflow associated with capital contributions to subsidiaries during the period. Cash provided by financing activities: Repurchase and retirement of shares to satisfy tax withholding requirements Other, net Cash and cash equivalents: Cash and Cash Equivalents, Period Increase (Decrease) [Abstract] INCOME TAXES Income Tax Disclosure [Text Block] Reconciliation of the beginning and ending balance of medical benefits payable [Roll Forward] Reconciliation of the beginning and ending balance of medical benefits payable [Roll Forward] A roll forward is a reconciliation of the beginning and ending balance of medical benefits payable. Beginning balance Acquisitions (divestitures) Medical benefits incurred related to: Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims [Abstract] Current year (1) Current Year Claims and Claims Adjustment Expense Prior years Total Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims Medical benefits paid related to: Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid [Abstract] Current year Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Current Year Prior years Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Prior Years Total Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid Ending balance Premium deficiency reserve Convertible Senior Notes Due 2021 Convertible Senior Notes Due 2021 [Member] Convertible Senior Notes Due 2021 [Member] Unsecured Debt Unsecured Debt [Member] Purchase price Cash purchase price (in dollars per share) Business Acquisition, Share Price Assumption of convertible debt Cash settlement of preferred shares Business Combination, Consideration Transferred, Payments to Repurchase Redeemable Preferred Stock Business Combination, Consideration Transferred, Payments to Repurchase Redeemable Preferred Stock Number of MSSP ACOs Number Of Accountable Care Organizations, Medicare Shared Savings Program Number Of Accountable Care Organizations, Medicare Shared Savings Program