Document and Entity Information	6 Months Ended
Document and Entity Information	Mar. 31, 2018	May 08, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	Blue Bird Corp
Entity Central Index Key	0001589526
Current Fiscal Year End Date	--09-29
Entity Filer Category	Accelerated Filer
Document Type	10-Q
Document Period End Date	Mar. 31, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q2
Amendment Flag	false
Entity Common Stock, Shares Outstanding		26,999,660

Condensed Consolidated Balance Sheets (USD $) In Thousands	Mar. 31, 2018	Sep. 30, 2017
Current assets
Cash and cash equivalents	$ 10,349	$ 62,616
Accounts receivable, net	12,190	10,148
Inventories	105,387	76,155
Other current assets	12,883	11,528
Total current assets	140,809	160,447
Property, plant and equipment, net	38,126	34,708
Goodwill	18,825	18,825
Intangible assets, net	56,476	57,481
Equity investment in affiliate	11,859	11,625
Deferred tax assets	10,129	11,755
Other assets	991	975
Total assets	$ 277,215	$ 295,816
Current liabilities
Accounts payable	$ 96,125	$ 87,331
Warranty	7,906	8,573
Accrued expenses	12,283	18,229
Deferred warranty income	7,204	6,776
Other current liabilities	6,716	9,847
Current portion of long-term debt	8,000	8,000
Total current liabilities	$ 138,234	$ 138,756
Long-term liabilities
Long-term debt	$ 139,608	$ 143,224
Warranty	11,377	12,337
Deferred warranty income	13,257	12,519
Other liabilities	15,618	15,064
Pension	29,073	32,426
Total long-term liabilities	208,933	215,570
Guarantees, commitments and contingencies (Note 6)
Stockholders' deficit
Preferred stock, $0.0001 par value, 10,000,000 shares authorized, 400,000 issued with liquidation preference of $40,000 at March 31, 2018 and September 30, 2017	$ 40,000	$ 40,000
Common stock, $0.0001 par value, 100,000,000 shares authorized, 23,912,188 and 23,739,344 issued and outstanding at March 31, 2018 and September 30, 2017, respectively	2	2
Additional paid-in capital	38,747	45,418
Accumulated deficit	(106,058)	(100,055)
Accumulated other comprehensive loss	(42,643)	(43,875)
Total stockholders' deficit	(69,952)	(58,510)
Total liabilities and stockholders' deficit	$ 277,215	$ 295,816

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2018	Sep. 30, 2017
Statement of Financial Position [Abstract]
Preferred Stock, Par Value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred Stock, Shares Authorized	10,000,000	10,000,000
Preferred Stock, Shares Issued	400,000	400,000
Preferred Stock, Liquidation Preference, Value	$ 40,000,000	$ 40,000,000
Common Stock, Par Value (in dollars per share)	$ 0.0001	$ 0.0001
Common Stock, Shares Authorized	100,000,000	100,000,000
Common Stock, Shares Issued	23,912,188	23,739,344
Common Stock, Shares Outstanding	23,912,188	23,739,344

Condensed Consolidated Statements of Operations (USD $) In Thousands, except Share data	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Apr. 01, 2017	Mar. 31, 2018	Apr. 01, 2017
Income Statement [Abstract]
Net sales	$ 216,628	$ 208,651	$ 379,177	$ 345,311
Cost of goods sold	194,960	184,002	336,861	302,464
Gross profit	$ 21,668	$ 24,649	$ 42,316	$ 42,847
Operating expenses
Selling, general and administrative expenses	$ 18,741	$ 19,259	$ 44,659	$ 37,451
Operating profit (loss)	2,927	5,390	(2,343)	5,396
Interest expense	(1,826)	(1,715)	(3,278)	(4,403)
Interest income	2	6	17	13
Other income (expense), net	1,020	(37)	1,190	(164)
Loss on debt extinguishment	0	0	0	(10,142)
Income (loss) before income taxes	2,123	3,644	(4,414)	(9,300)
Income tax (expense) benefit	(471)	(1,108)	(1,823)	2,564
Equity in net income of non-consolidated affiliate	184	212	234	961
Net income (loss)	$ 1,836	$ 2,748	$ (6,003)	$ (5,775)
Earnings per share:
Net income (loss) (from above)	$ 1,836	$ 2,748	$ (6,003)	$ (5,775)
Less: preferred stock dividends	763	1,017	1,533	1,970
Net income (loss) available to common stockholders	$ 1,073	$ 1,731	$ (7,536)	$ (7,745)
Basic weighted average shares outstanding	23,899,772	23,048,517	23,911,909	22,822,416
Diluted weighted average shares outstanding	25,127,082	24,590,905	23,911,909	22,822,416
Basic earnings (loss) per share (in dollars per share)	$ 0.04	$ 0.08	$ (0.32)	$ (0.34)
Diluted earnings (loss) per share (in dollars per share)	$ 0.04	$ 0.07	$ (0.32)	$ (0.34)

Condensed Consolidated Statements of Comprehensive Income (Loss) (USD $) In Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Apr. 01, 2017	Mar. 31, 2018	Apr. 01, 2017
Statement of Comprehensive Income [Abstract]
Net loss	$ 1,836	$ 2,748	$ (6,003)	$ (5,775)
Other comprehensive income, net of tax
Net change in defined benefit pension plan	$ 669	$ 1,007	$ 1,232	$ 2,013
Net unrealized (loss) gain on cash flow hedges	0	(47)	0	102
Total other comprehensive income	669	960	1,232	2,115
Comprehensive income (loss)	$ 2,505	$ 3,708	$ (4,771)	$ (3,660)

Condensed Consolidated Statements of Cash Flows (USD $) In Thousands	6 Months Ended
	Mar. 31, 2018	Apr. 01, 2017
Cash flows from operating activities
Net loss	$ (6,003)	$ (5,775)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	$ 4,173	$ 4,101
Amortization of debt costs	384	713
Share-based compensation	1,510	410
Equity in net income of affiliate	(234)	(961)
Loss (gain) on disposal of fixed assets	78	(46)
Deferred taxes	1,098	(2,964)
Amortization of deferred actuarial pension losses	1,760	3,145
Loss on debt extinguishment	0	10,142
Unrealized gains on foreign currency hedges	$ (1,036)	$ 0
Changes in assets and liabilities:
Accounts receivable	$ (2,042)	$ 13,444
Inventories	(29,232)	(56,618)
Other assets	(335)	(1,112)
Accounts payable	9,151	30,961
Accrued expenses, pension and other liabilities	(12,329)	(4,765)
Total adjustments	(27,054)	(3,550)
Total cash used in operating activities	$ (33,057)	$ (9,325)
Cash flows from investing activities
Cash paid for fixed assets	$ (7,021)	$ (5,159)
Proceeds from sale of fixed assets	0	46
Total cash used in investing activities	$ (7,021)	$ (5,113)
Cash flows from financing activities
Repayments under the former senior term loan	$ 0	$ (161,500)
Borrowings under the new term loan	0	156,887
Repayments under the new term loan	(4,000)	(2,000)
Cash paid for capital leases	(77)	(79)
Cash paid for debt issuance costs	0	(271)
Cash paid to extinguish debt	0	(507)
Payment of dividends on preferred stock	(1,533)	(1,970)
Cash paid for employee taxes on vested restricted shares and stock option exercises	(571)	(981)
Proceeds from exercises of warrants	9,504	10,982
Common stock repurchases under the share repurchase program	(15,512)	0
Total cash (used in) provided by financing activities	(12,189)	561
Change in cash and cash equivalents	(52,267)	(13,877)
Cash and cash equivalents, beginning of period	62,616	52,309
Cash and cash equivalents, end of period	$ 10,349	$ 38,432
Supplemental disclosures of cash flow information
Interest paid, net of interest received	$ 2,950	$ 3,294
Income tax paid, net of tax refunds	$ 3,596	$ 1,233
Non-cash investing and financing activities:
Change in accounts payable for capital additions to property, plant and equipment	$ (357)	$ (2,178)
Cashless exercise of stock options	$ 897	$ 4,124

Nature of Business and Basis of Presentation	6 Months Ended
Nature of Business and Basis of Presentation	Mar. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Business and Basis of Presentation	1. Nature of Business and Basis of Presentation Nature of Business Blue Bird Body Company, a wholly-owned subsidiary of Blue Bird Corporation, was incorporated in 1958 and has manufactured, assembled and sold school buses to a variety of municipal, federal and commercial customers since 1927. The majority of Blue Bird’s sales are made to an independent distributor network, which in turn sells buses to ultimate end users. We are headquartered in Macon, Georgia. References in these notes to financial statements to “Blue Bird”, the “Company,” “we,” “our,” or “us” refer to Blue Bird Corporation and its wholly-owned subsidiaries, unless the context specifically indicates otherwise. Basis of Presentation The accompanying unaudited condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All significant inter-company transactions and accounts have been eliminated in consolidation. The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles for interim financial reporting and Article 8 of Regulation S-X. The Company’s fiscal year ends on the Saturday closest to September 30 with its quarters consisting of thirteen weeks in most years. In fiscal year 2018, there is a total of 52 weeks. For fiscal years 2018 and 2017, the second quarters both included 13 weeks. In the opinion of management, all adjustments considered necessary for a fair presentation of financial results have been made. Such adjustments consist of only those of a normal recurring nature. Operating results for any interim period are not necessarily indicative of the results that may be expected for the entire year. Accordingly, they do not include all of the information and footnotes required by generally accepted accounting principles for complete financial statements. The Condensed Consolidated Balance Sheet data as of September 30, 2017 was derived from the Company’s audited financial statements but do not include all disclosures required by generally accepted accounting principles. For additional information, including the Company’s significant accounting policies, refer to the consolidated financial statements and related footnotes for the fiscal year ended September 30, 2017 as set forth in the Company's 2017 Form 10-K filed on December 8, 2017. Use of Estimates and Assumptions The preparation of financial statements in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) requires management to make estimates and assumptions. At the date of the financial statements, these estimates and assumptions affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities, and during the reporting period, these estimates and assumptions affect the reported amounts of revenues and expenses. For example, significant management judgments are required in determining excess, obsolete, or unsalable inventory, allowance for doubtful accounts, potential impairment of long-lived assets, goodwill and intangibles, the accounting for self-insurance reserves, warranty reserves, pension obligations, income taxes, environmental liabilities and contingencies. Future events and their effects cannot be predicted with certainty, and, accordingly, the Company’s accounting estimates require the exercise of judgment. The accounting estimates used in the preparation of the Company’s condensed consolidated financial statements may change as new events occur, as more experience is acquired, as additional information is obtained and as the Company’s operating environment changes. The Company evaluates and updates its assumptions and estimates on an ongoing basis and may employ outside experts to assist in the Company’s evaluations. Actual results could differ from the estimates that the Company has used.

Summary of Significant Accounting Policies and Recently Issued Accounting Standards	6 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies and Recently Issued Accounting Standards	2. Summary of Significant Accounting Policies and Recent Accounting Standards The Company’s significant accounting policies are described in the Company’s 2017 Form 10-K, filed with the SEC on December 8, 2017. Our senior management has reviewed these significant accounting policies and related disclosures and determined that there were no significant changes in our critical accounting policies in the six months ended March 31, 2018. Recently Issued Accounting Standards In February 2018, the FASB issued ASU No. 2018-02, Income Statement - Reporting Comprehensive Income (Topic 220). This ASU provides guidance on a reclassification from accumulated other comprehensive income ("AOCI") to retained earnings for the effect of the tax rate change resulting from the Tax Cuts and Jobs Act (H.R.1) (the "Tax Act"). The amendments eliminate the stranded tax effects resulting from the Tax Act and will improve the usefulness of information reported to financial statement users. This ASU is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018, with early adoption permitted. Should we elect to apply this optional ASU, it will be effective for us in the first quarter of fiscal 2020. We are currently evaluating the impact this ASU may have on our consolidated financial statements. Recently Adopted Accounting Standards In the first quarter of fiscal 2018, the Company adopted ASU No. 2015-11, Simplifying the Measurement of Inventory, which requires inventory to be measured at the lower of cost or net realizable value. The adoption of this pronouncement did not have any impact on any component of our financial statements.

Supplemental Financial Information

6 Months Ended

Mar. 31, 2018

Condensed Financial Information [Abstract]

Supplemental Financial Information

3. Supplemental Financial Information

Inventory

The Company values inventories at the lower of cost or net realizable value. The Company uses a standard costing methodology, which approximates cost on a first-in, first-out basis. The Company reviews the standard costs of raw materials, work-in-process and finished goods inventory on a periodic basis to ensure that its inventories approximate current actual costs. Manufacturing cost includes raw materials, direct labor and manufacturing overhead. The following table presents the components of inventory at the dates indicated:



(in thousands of dollars)	March 31, 2018		September 30, 2017
Raw materials	$	63,282	$	54,379
Work in process	21,492		14,660
Finished goods	20,613		7,116
Total inventory	$	105,387	$	76,155

Product Warranties

The Company’s products are generally warranted against defects in material and workmanship for a period of one to five years. A provision for estimated warranty costs is recorded at the time the unit is sold. The methodology to determine the warranty reserve calculates average expected warranty claims using warranty claims by body type, by month, over the life of the bus, which is then multiplied by remaining months under warranty, by warranty type. Management believes the methodology provides an accurate reserve estimate. Actual claims incurred could differ from the original estimates, requiring future adjustments.

The following table reflects activity in accrued warranty cost (current and long-term portion combined) for the periods presented:



	Three Months Ended						Six Months Ended
(in thousands of dollars)	March 31, 2018			April 1, 2017			March 31, 2018			April 1, 2017
Balance at beginning of period	$	19,788		$	18,318		$	20,910		$	19,444
Add current period accruals	2,406			2,327			4,365			3,780
Current period reductions of accrual	(2,911		)	(2,033		)	(5,992		)	(4,612		)
Balance at end of period	$	19,283		$	18,612		$	19,283		$	18,612

The Company also sells extended warranties related to its products. Revenue related to these contracts is recognized on a straight-line basis over the contract period and costs thereunder are expensed as incurred. All warranty expenses are recorded in the cost of goods sold line on the Condensed Consolidated Statements of Operations. The methodology to determine the short-term extended warranty income reserve is based on twelve months of the remaining warranty value for each effective extended warranty at the balance sheet date.

The following table reflects activity in deferred warranty income (current and long-term portions combined), for the sale of extended warranties of two to five years, for the periods presented:



	Three Months Ended						Six Months Ended
(in thousands of dollars)	March 31, 2018			April 1, 2017			March 31, 2018			April 1, 2017
Balance at beginning of period	$	19,208		$	15,809		$	19,295		$	16,187
Add current period deferred income	2,763			2,244			4,826			3,373
Current period recognition of income	(1,510		)	(1,399		)	(3,660		)	(2,906		)
Balance at end of period	$	20,461		$	16,654		$	20,461		$	16,654

Self-Insurance

The following table reflects our total accrued self-insurance liability, comprised of workers compensation and health insurance related claims, at the dates indicated:



(in thousands of dollars)	March 31, 2018		September 30, 2017
Current portion	$	3,305	$	3,194
Long-term portion	2,413		2,251
Total accrued self-insurance	$	5,718	$	5,445

The current and long-term portions of the accrued self-insurance liability are reflected in accrued expenses and other liabilities, respectively, on the Condensed Consolidated Balance Sheets.

Shipping and Handling Revenues

Shipping and handling revenues represent costs billed to customers and are included in net sales. Shipping and handling costs incurred are included in cost of goods sold. Shipping and handling revenues were $3.6 million and $3.0 million for the three months ended March 31, 2018 and April 1, 2017, respectively, and $7.0 million and $6.2 million for the six months ended March 31, 2018 and April 1, 2017, respectively. The related cost of goods sold was $3.1 million and $2.6 million for the three months ended March 31, 2018 and April 1, 2017, respectively, and $5.9 million and $5.3 million for the six months ended March 31, 2018 and April 1, 2017, respectively.

Pension Expense

Components of net periodic pension benefit cost were as follows for the periods presented:



	Three Months Ended						Six Months Ended
(in thousands of dollars)	March 31, 2018			April 1, 2017			March 31, 2018			April 1, 2017
Interest cost	$	1,357		$	1,265		$	2,714		$	2,531
Expected return on plan assets	(1,776		)	(1,589		)	(3,552		)	(3,179		)
Amortization of prior loss	880			1,572			1,760			3,145
Net periodic benefit cost	$	461		$	1,248		$	922		$	2,497
Amortization of prior loss, recognized in other comprehensive income	880			1,572			1,760			3,145
Total recognized in net periodic pension benefit cost and other comprehensive income	$	(419	)	$	(324	)	$	(838	)	$	(648	)

Warrants

At March 31, 2018, there were a total of 3,272,358 warrants outstanding to purchase 1,636,179 shares of our Common Stock.

Debt

6 Months Ended

Mar. 31, 2018

Debt Disclosure [Abstract]

Debt

4. Debt

Debt consisted of the following at the dates indicated:



(in thousands of dollars)	March 31, 2018		September 30, 2017
2021 term loan, net of deferred financing costs of $2,392 and $2,776, respectively	$	147,608	$	151,224
Less: current portion of long-term debt	8,000		8,000
Long-term debt, net of current portion	$	139,608	$	143,224

Term loans are recognized on the Condensed Consolidated Balance Sheets at the unpaid principal balance, and are not subject to fair value measurement; however, given the variable rates on the loans, the Company estimates that the unpaid principal balance approximates fair value. If measured at fair value in the financial statements, the term loans would be classified as Level 2 in the fair value hierarchy. At March 31, 2018 and September 30, 2017, $150.0 million and $154.0 million, respectively, were outstanding on the term loans.

At March 31, 2018 and September 30, 2017, the stated interest rates on the term loans were 3.4% and 2.8%, respectively. At March 31, 2018 and September 30, 2017, the weighted-average annual effective interest rates for the term loans were 3.8% and 4.5%, respectively, which included amortization of the deferred financing costs.

No borrowings were outstanding on the Revolving Credit Facility at March 31, 2018; however, since $6.9 million of Letters of Credit were outstanding on March 31, 2018, the Company would have been able to borrow $68.1 million on the revolving line of credit.

Interest expense on all indebtedness was $1.8 million and $1.7 million for the three months ended March 31, 2018 and April 1, 2017, respectively, and $3.3 million and $4.4 million for the six months ended March 31, 2018 and April 1, 2017, respectively.

The schedules of remaining principal maturities for the term loan for the next five fiscal years are as follows:



(in thousands of dollars)
Year	Principal Payments
2018	$	4,000
2019	8,000
2020	11,000
2021	15,000
2022	112,000
Total remaining principal payments	$	150,000

Income Taxes	6 Months Ended
Income Taxes	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	5. Income Taxes Income tax provisions for interim periods are based on estimated annual income tax rates, adjusted to reflect the effects of any significant infrequent or unusual items which are required to be discretely recognized within the current interim period. The effective tax rates in the periods presented are largely based upon the forecast pre-tax earnings mix and allocation of certain expenses in various taxing jurisdictions where the Company conducts its business, primarily the United States. The effective tax rate for the three month period ended March 31, 2018 was 22.2%, which differed from the transitional 2018 statutory federal income tax rate of 24.5%. The difference is mainly due to normal tax rate benefit items, such as the domestic production activities deduction, state tax credits, and share based award related deductions in excess of recorded book expense. These benefits were partially offset by accrued interest and penalties on uncertain tax positions. The effective tax rate for the three month period ended April 1, 2017 was 30.4%, which differed from the statutory federal income tax rate of 35%, mainly due to normal tax rate benefit items, such as the domestic production activities deduction, state tax credits, and share based award related deductions in excess of recorded book expense. These benefits were partially offset by discrete expense items, the largest being interest and penalties on uncertain tax positions. The effective tax rate for the six month period ended March 31, 2018 was (41.3)% and significantly differed from the transitional 2018 statutory federal income tax rate of 24.5%. The difference is mainly due to $2.4 million in period expense recorded in the prior fiscal quarter to reflect the newly enacted Tax Act. The Tax Act adjustments include resetting our deferred tax accounts to the new rates as well as $1.1 million of expense from increasing the carrying value of our uncertain tax positions, and $0.5 million of additional valuation allowance for our foreign tax credit carryforward. Our rate was further impacted by accrued interest and penalties on uncertain tax positions. These items were partially offset by normal tax rate benefit items, such as the domestic production activities deduction, state tax credits, and share based award related deductions in excess of recorded book expense. The effective tax rate for the six month period ended April 1, 2017 was 27.6% and differed from the statutory federal income tax rate of 35%, primarily from normal tax rate benefit items, such as the domestic production activities deduction, state tax credits, and share based award related deductions in excess of recorded book expense. These benefits were partially offset by discrete expense items, the largest being interest and penalties on uncertain tax positions.

Guarantees, Commitments and Contingencies	6 Months Ended
Guarantees, Commitments and Contingencies	Mar. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Guarantees, Commitments and Contingencies	6. Guarantees, Commitments and Contingencies Litigation At March 31, 2018, the Company had a number of product liability and other cases pending. Management believes that, considering the Company’s insurance coverage and its intention to vigorously defend its positions, the ultimate resolution of these matters will not have a material adverse effect on the Company’s financial statements. Environmental The Company is subject to a variety of environmental regulations relating to the use, storage, discharge and disposal of hazardous materials used in its manufacturing processes. Failure by the Company to comply with present and future regulations could subject it to future liabilities. In addition, such regulations could require the Company to acquire costly equipment or to incur other significant expenses to comply with environmental regulations. The Company is currently not involved in any material environmental proceedings and therefore management believes that the resolution of environmental matters will not have a material adverse effect on the Company’s financial statements.

Segment Information

6 Months Ended

Mar. 31, 2018

Segment Reporting [Abstract]

Segment Information

7. Segment Information

We manage our business in two operating segments, which are also our reportable segments. The Bus segment includes the manufacturing and assembly of buses to be sold to a variety of customers across the United States, Canada and in international markets. The Parts segment consists primarily of the purchase of parts from third parties to be sold to dealers within the Company’s network. Financial information is reported on the basis that it is used internally by the chief operating decision maker (the “CODM”) in evaluating segment performance and deciding how to allocate resources. The President and Chief Executive Officer of the Company has been identified as the CODM. Management evaluates the segments based primarily upon revenues and gross profit. A measure of assets is not applicable, as segment assets are not regularly reviewed by the CODM for evaluating performance or allocating resources. The tables below present segment net sales and gross profit for the periods presented:

Net sales



	Three Months Ended				Six Months Ended
(in thousands of dollars)	March 31, 2018		April 1, 2017		March 31, 2018		April 1, 2017
Bus	$	201,774	$	193,760	$	349,872	$	316,166
Parts	14,854		14,891		29,305		29,145
Segment net sales	$	216,628	$	208,651	$	379,177	$	345,311

Gross profit



	Three Months Ended				Six Months Ended
(in thousands of dollars)	March 31, 2018		April 1, 2017		March 31, 2018		April 1, 2017
Bus	$	16,343	$	19,229	$	31,720	$	32,391
Parts	5,325		5,420		10,596		10,456
Segment gross profit	$	21,668	$	24,649	$	42,316	$	42,847

The following table is a reconciliation of segment gross profit to consolidated income (loss) before income taxes for the periods presented:



	Three Months Ended						Six Months Ended
(in thousands of dollars)	March 31, 2018			April 1, 2017			March 31, 2018			April 1, 2017
Segment gross profit	$	21,668		$	24,649		$	42,316		$	42,847
Adjustments:
Selling, general and administrative expenses	(18,741		)	(19,259		)	(44,659		)	(37,451		)
Interest expense	(1,826		)	(1,715		)	(3,278		)	(4,403		)
Interest income	2			6			17			13
Other income (expense), net	1,020			(37		)	1,190			(164		)
Loss on debt extinguishment	—			—			—			(10,142		)
Income (loss) before income taxes	$	2,123		$	3,644		$	(4,414	)	$	(9,300	)

Sales are attributable to geographic areas based on customer location and were as follows for the periods presented:



	Three Months Ended				Six Months Ended
(in thousands of dollars)	March 31, 2018		April 1, 2017		March 31, 2018		April 1, 2017
United States	$	198,414	$	186,932	$	353,062	$	316,678
Canada	17,609		21,120		22,459		25,985
Rest of world	605		599		3,656		2,648
Total net sales	$	216,628	$	208,651	$	379,177	$	345,311

Earnings Per Share

6 Months Ended

Mar. 31, 2018

Earnings Per Share [Abstract]

Earnings Per Share

8. Earnings Per Share

We incurred a net loss for six months ended March 31, 2018 and April 1, 2017. As a result, basic and diluted shares outstanding are equal to each other for those periods due to the exclusion of potentially dilutive shares from the calculation of earnings per share as the effect would be anti-dilutive. Potentially dilutive shares excluded from the calculation were 4,701,112 and 5,826,988 for the six months ended March 31, 2018 and April 1, 2017, respectively.

The following table presents the earnings per share computation for the period presented when there are dilutive shares:



	Three Months Ended
(in thousands except for share data)	March 31, 2018		April 1, 2017
Numerator:
Net income	$	1,836	$	2,748
Less: convertible preferred stock dividends	763		1,017
Net income available to common stockholders	$	1,073	$	1,731

Basic earnings per share (1):
Weighted average common shares outstanding	23,899,772		23,048,517
Basic earnings per share	$	0.04	$	0.08

Diluted earnings per share (2):
Weighted average common shares outstanding	23,899,772		23,048,517
Weighted average dilutive securities, convertible preferred stock	—		—
Weighted average dilutive securities, restricted stock	14,797		—
Weighted average dilutive securities, warrants	939,107		1,308,774
Weighted average dilutive securities, stock options	273,406		233,614
Weighted average shares and dilutive potential common shares	25,127,082		24,590,905
Diluted earnings per share	$	0.04	$	0.07

(1) Basic earnings per share is calculated by dividing income available to common stockholders by the weighted average common shares outstanding during the period.

(2) Diluted earnings per share is calculated by adjusting the weighted average shares outstanding for the dilutive effect of common stock equivalents outstanding during the period, determined by using the treasury-stock method, and adjusting for the dilutive effect of our convertible preferred stock, determined by using the if-converted method. For the three months ended March 31, 2018 and April 1, 2017, 3,451,251 and 4,314,064 shares, respectively, of convertible preferred stock were excluded from the dilutive calculation as the if-converted impact would be anti-dilutive.

Share-Based Compensation

6 Months Ended

Mar. 31, 2018

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Share-Based Compensation

9. Share-Based Compensation

Restricted Stock Awards

The following table summarizes the Company's restricted stock awards ("RSAs") and restricted stock units ("RSUs") award activity for the period presented:



	Six Months Ended
	March 31, 2018
Restricted Stock Activity	Number of Shares		Weighted-Average Grant Date Fair Value
Balance, beginning of period	75,590		$	15.83
Granted	107,720		18.10
Vested	(53,355	)	15.50
Forfeited/canceled	(8,076	)	15.62
Balance, end of period	121,879		17.99

Compensation expense for restricted stock awards, recognized in selling, general and administrative expenses on the Condensed Consolidated Statements of Operations, was $0.5 million and $0.9 million with associated tax benefits of $0.1 million and $0.2 million for the three and six months ended March 31, 2018, respectively. At March 31, 2018, unrecognized compensation cost related to restricted stock awards totaled $1.4 million and is expected to be recognized over a weighted-average period of nine months.

Stock Option Awards

The following table summarizes the Company's stock option activity for the period presented:



	Six Months Ended
	March 31, 2018
Stock Option Award Activity	Number of Options		Weighted Average Exercise Price per Share ($)
Outstanding options, beginning of period	623,962		$	11.15
Granted	215,530		16.61
Exercised (1)	(73,102	)	12.27
Forfeited	(19,030	)	15.50
Outstanding options, end of period (2)	747,360		12.50
Fully vested and exercisable options, end of period (3)	535,302		10.87

(1) Stock options exercised in the period had an aggregate intrinsic value totaling $0.6 million.

(2) Stock options outstanding at the end of the period had an aggregate intrinsic value totaling $8.4 million.

(3) Fully vested and exercisable options at the end of the period had an aggregate intrinsic value totaling $6.9 million with a weighted average contractual remaining term of 7.3 years.

Compensation expense for stock option awards, recognized in selling, general and administrative expenses on the Consolidated Statements of Operations, was $0.3 million and $0.5 million with associated tax benefits of $0.0 million and $0.1 million for the three and six months ended March 31, 2018, respectively. At March 31, 2018, unrecognized compensation cost related to stock option awards totaled $0.9 million and is expected to be recognized over a weighted-average period of nine months.

The fair value of each option award at grant date was estimated using the Black-Scholes option-pricing model with the following assumptions and resulting grant-date fair value during the period presented:



	Six Months Ended
	March 31, 2018
Expected volatility	29.2		%
Expected dividend yield	0		%
Risk-free interest rate	2.16		%
Expected term (in years)	5.0 - 5.5
Weighted-average grant-date fair value	$	6.15

Accumulated Other Comprehensive Income

6 Months Ended

Mar. 31, 2018

Equity [Abstract]

Accumulated Other Comprehensive Income

10. Accumulated Other Comprehensive Income

The following table provides information on changes in accumulated other comprehensive income (“AOCI”) for the periods presented:



	Three Months Ended									Six Months Ended
(in thousands)	Defined Benefit Pension Plan			Cash Flow Hedges (Effective Portion)			Total AOCI			Defined Benefit Pension Plan			Cash Flow Hedges (Effective Portion)			Total AOCI
March 31, 2018
Balance, beginning of period	$	(43,312	)	$	—		$	(43,312	)	$	(43,875	)	$	—		$	(43,875	)
Other comprehensive income, gross	—			—			—			—			—			—
Amounts reclassified from other comprehensive income and included in earnings	880			—			880			1,760			—			1,760
Total other comprehensive income, before taxes	880			—			880			1,760			—			1,760
Income tax expense	(211		)	—			(211		)	(528		)	—			(528		)
Balance, end of period	$	(42,643	)	$	—		$	(42,643	)	$	(42,643	)	$	—		$	(42,643	)

April 1, 2017
Balance, beginning of period	$	(57,872	)	$	136		$	(57,736	)	$	(58,878	)	$	(13	)	$	(58,891	)
Other comprehensive (loss) income, gross	—			(81		)	(81		)	—			383			383
Amounts reclassified from other comprehensive income and included in earnings	1,572			8			1,580			3,145			(227		)	2,918
Total other comprehensive income (loss), before taxes	1,572			(73		)	1,499			3,145			156			3,301
Income tax (expense) benefit	(565		)	26			(539		)	(1,132		)	(54		)	(1,186		)
Balance, end of period	$	(56,865	)	$	89		$	(56,776	)	$	(56,865	)	$	89		$	(56,776	)

Subsequent Event	6 Months Ended
Subsequent Event	Mar. 31, 2018
Subsequent Events [Abstract]
Subsequent Event	11. Subsequent Event On April 24, 2018, the Company exercised its right to convert the maximum number of outstanding shares of the 7.625% Convertible Cumulative Perpetual Preferred Stock, Series A (“Series A Preferred Stock”) into shares of common stock, $0.0001 per share, of the Company (“Common Stock”). The conversion was subject to a beneficial ownership limitation, which prohibits the Company from effecting a conversion of Series A Preferred Stock to the extent that, after giving effect to such conversion, the holder of the Series A Preferred Stock would beneficially own in excess of 9.99% of the outstanding Common Stock. As a result of this conversion, a total of 307,000 shares of Series A Preferred Stock were converted into 2,649,962 shares of common stock based on the conversion rate of 8.6318 shares of Common Stock for each share of Series A Preferred Stock being converted. After the conversion, 93,000 shares of Series A Preferred Stock were outstanding.

Nature of Business and Basis of Presentation (Policies)	6 Months Ended
Nature of Business and Basis of Presentation (Policies)	Mar. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All significant inter-company transactions and accounts have been eliminated in consolidation. The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles for interim financial reporting and Article 8 of Regulation S-X. The Company’s fiscal year ends on the Saturday closest to September 30 with its quarters consisting of thirteen weeks in most years. In fiscal year 2018, there is a total of 52 weeks. For fiscal years 2018 and 2017, the second quarters both included 13 weeks. In the opinion of management, all adjustments considered necessary for a fair presentation of financial results have been made. Such adjustments consist of only those of a normal recurring nature. Operating results for any interim period are not necessarily indicative of the results that may be expected for the entire year. Accordingly, they do not include all of the information and footnotes required by generally accepted accounting principles for complete financial statements. The Condensed Consolidated Balance Sheet data as of September 30, 2017 was derived from the Company’s audited financial statements but do not include all disclosures required by generally accepted accounting principles. For additional information, including the Company’s significant accounting policies, refer to the consolidated financial statements and related footnotes for the fiscal year ended September 30, 2017 as set forth in the Company's 2017 Form 10-K filed on December 8, 2017.
Use of Estimates and Assumptions	Use of Estimates and Assumptions The preparation of financial statements in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) requires management to make estimates and assumptions. At the date of the financial statements, these estimates and assumptions affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities, and during the reporting period, these estimates and assumptions affect the reported amounts of revenues and expenses. For example, significant management judgments are required in determining excess, obsolete, or unsalable inventory, allowance for doubtful accounts, potential impairment of long-lived assets, goodwill and intangibles, the accounting for self-insurance reserves, warranty reserves, pension obligations, income taxes, environmental liabilities and contingencies. Future events and their effects cannot be predicted with certainty, and, accordingly, the Company’s accounting estimates require the exercise of judgment. The accounting estimates used in the preparation of the Company’s condensed consolidated financial statements may change as new events occur, as more experience is acquired, as additional information is obtained and as the Company’s operating environment changes. The Company evaluates and updates its assumptions and estimates on an ongoing basis and may employ outside experts to assist in the Company’s evaluations. Actual results could differ from the estimates that the Company has used.
Recently Issued Accounting Standards and Recently Adopted Accounting Standards	Recently Issued Accounting Standards In February 2018, the FASB issued ASU No. 2018-02, Income Statement - Reporting Comprehensive Income (Topic 220). This ASU provides guidance on a reclassification from accumulated other comprehensive income ("AOCI") to retained earnings for the effect of the tax rate change resulting from the Tax Cuts and Jobs Act (H.R.1) (the "Tax Act"). The amendments eliminate the stranded tax effects resulting from the Tax Act and will improve the usefulness of information reported to financial statement users. This ASU is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018, with early adoption permitted. Should we elect to apply this optional ASU, it will be effective for us in the first quarter of fiscal 2020. We are currently evaluating the impact this ASU may have on our consolidated financial statements. Recently Adopted Accounting Standards In the first quarter of fiscal 2018, the Company adopted ASU No. 2015-11, Simplifying the Measurement of Inventory, which requires inventory to be measured at the lower of cost or net realizable value. The adoption of this pronouncement did not have any impact on any component of our financial statements.

Supplemental Financial Information (Tables)

6 Months Ended

Mar. 31, 2018

Condensed Financial Information [Abstract]

Inventory

Manufacturing cost includes raw materials, direct labor and manufacturing overhead. The following table presents the components of inventory at the dates indicated:



(in thousands of dollars)	March 31, 2018		September 30, 2017
Raw materials	$	63,282	$	54,379
Work in process	21,492		14,660
Finished goods	20,613		7,116
Total inventory	$	105,387	$	76,155

Product Warranties

The following table reflects activity in deferred warranty income (current and long-term portions combined), for the sale of extended warranties of two to five years, for the periods presented:



	Three Months Ended						Six Months Ended
(in thousands of dollars)	March 31, 2018			April 1, 2017			March 31, 2018			April 1, 2017
Balance at beginning of period	$	19,208		$	15,809		$	19,295		$	16,187
Add current period deferred income	2,763			2,244			4,826			3,373
Current period recognition of income	(1,510		)	(1,399		)	(3,660		)	(2,906		)
Balance at end of period	$	20,461		$	16,654		$	20,461		$	16,654

The following table reflects activity in accrued warranty cost (current and long-term portion combined) for the periods presented:



	Three Months Ended						Six Months Ended
(in thousands of dollars)	March 31, 2018			April 1, 2017			March 31, 2018			April 1, 2017
Balance at beginning of period	$	19,788		$	18,318		$	20,910		$	19,444
Add current period accruals	2,406			2,327			4,365			3,780
Current period reductions of accrual	(2,911		)	(2,033		)	(5,992		)	(4,612		)
Balance at end of period	$	19,283		$	18,612		$	19,283		$	18,612

Self-Insurance

The following table reflects our total accrued self-insurance liability, comprised of workers compensation and health insurance related claims, at the dates indicated:



(in thousands of dollars)	March 31, 2018		September 30, 2017
Current portion	$	3,305	$	3,194
Long-term portion	2,413		2,251
Total accrued self-insurance	$	5,718	$	5,445

Pension Expense

Components of net periodic pension benefit cost were as follows for the periods presented:



	Three Months Ended						Six Months Ended
(in thousands of dollars)	March 31, 2018			April 1, 2017			March 31, 2018			April 1, 2017
Interest cost	$	1,357		$	1,265		$	2,714		$	2,531
Expected return on plan assets	(1,776		)	(1,589		)	(3,552		)	(3,179		)
Amortization of prior loss	880			1,572			1,760			3,145
Net periodic benefit cost	$	461		$	1,248		$	922		$	2,497
Amortization of prior loss, recognized in other comprehensive income	880			1,572			1,760			3,145
Total recognized in net periodic pension benefit cost and other comprehensive income	$	(419	)	$	(324	)	$	(838	)	$	(648	)

Debt (Tables)

6 Months Ended

Mar. 31, 2018

Debt Disclosure [Abstract]

Schedule of Long-term Debt Instruments

Debt consisted of the following at the dates indicated:



(in thousands of dollars)	March 31, 2018		September 30, 2017
2021 term loan, net of deferred financing costs of $2,392 and $2,776, respectively	$	147,608	$	151,224
Less: current portion of long-term debt	8,000		8,000
Long-term debt, net of current portion	$	139,608	$	143,224

Schedule of Maturities of Long-term Debt

The schedules of remaining principal maturities for the term loan for the next five fiscal years are as follows:



(in thousands of dollars)
Year	Principal Payments
2018	$	4,000
2019	8,000
2020	11,000
2021	15,000
2022	112,000
Total remaining principal payments	$	150,000

Segment Information (Tables)

6 Months Ended

Mar. 31, 2018

Segment Reporting [Abstract]

Schedule of Segment Reporting Information, by Segment

The tables below present segment net sales and gross profit for the periods presented:

Net sales



	Three Months Ended				Six Months Ended
(in thousands of dollars)	March 31, 2018		April 1, 2017		March 31, 2018		April 1, 2017
Bus	$	201,774	$	193,760	$	349,872	$	316,166
Parts	14,854		14,891		29,305		29,145
Segment net sales	$	216,628	$	208,651	$	379,177	$	345,311

Gross profit



	Three Months Ended				Six Months Ended
(in thousands of dollars)	March 31, 2018		April 1, 2017		March 31, 2018		April 1, 2017
Bus	$	16,343	$	19,229	$	31,720	$	32,391
Parts	5,325		5,420		10,596		10,456
Segment gross profit	$	21,668	$	24,649	$	42,316	$	42,847

Reconciliation of Operating Profit (Loss) from Segments to Consolidated

The following table is a reconciliation of segment gross profit to consolidated income (loss) before income taxes for the periods presented:



	Three Months Ended						Six Months Ended
(in thousands of dollars)	March 31, 2018			April 1, 2017			March 31, 2018			April 1, 2017
Segment gross profit	$	21,668		$	24,649		$	42,316		$	42,847
Adjustments:
Selling, general and administrative expenses	(18,741		)	(19,259		)	(44,659		)	(37,451		)
Interest expense	(1,826		)	(1,715		)	(3,278		)	(4,403		)
Interest income	2			6			17			13
Other income (expense), net	1,020			(37		)	1,190			(164		)
Loss on debt extinguishment	—			—			—			(10,142		)
Income (loss) before income taxes	$	2,123		$	3,644		$	(4,414	)	$	(9,300	)

Revenue from External Customers by Geographic Areas

Sales are attributable to geographic areas based on customer location and were as follows for the periods presented:



	Three Months Ended				Six Months Ended
(in thousands of dollars)	March 31, 2018		April 1, 2017		March 31, 2018		April 1, 2017
United States	$	198,414	$	186,932	$	353,062	$	316,678
Canada	17,609		21,120		22,459		25,985
Rest of world	605		599		3,656		2,648
Total net sales	$	216,628	$	208,651	$	379,177	$	345,311

Earnings Per Share (Tables)

6 Months Ended

Mar. 31, 2018

Earnings Per Share [Abstract]

Schedule of Earnings Per Share, Basic and Diluted

The following table presents the earnings per share computation for the period presented when there are dilutive shares:



	Three Months Ended
(in thousands except for share data)	March 31, 2018		April 1, 2017
Numerator:
Net income	$	1,836	$	2,748
Less: convertible preferred stock dividends	763		1,017
Net income available to common stockholders	$	1,073	$	1,731

Basic earnings per share (1):
Weighted average common shares outstanding	23,899,772		23,048,517
Basic earnings per share	$	0.04	$	0.08

Diluted earnings per share (2):
Weighted average common shares outstanding	23,899,772		23,048,517
Weighted average dilutive securities, convertible preferred stock	—		—
Weighted average dilutive securities, restricted stock	14,797		—
Weighted average dilutive securities, warrants	939,107		1,308,774
Weighted average dilutive securities, stock options	273,406		233,614
Weighted average shares and dilutive potential common shares	25,127,082		24,590,905
Diluted earnings per share	$	0.04	$	0.07

(1) Basic earnings per share is calculated by dividing income available to common stockholders by the weighted average common shares outstanding during the period.

(2) Diluted earnings per share is calculated by adjusting the weighted average shares outstanding for the dilutive effect of common stock equivalents outstanding during the period, determined by using the treasury-stock method, and adjusting for the dilutive effect of our convertible preferred stock, determined by using the if-converted method. For the three months ended March 31, 2018 and April 1, 2017, 3,451,251 and 4,314,064 shares, respectively, of convertible preferred stock were excluded from the dilutive calculation as the if-converted impact would be anti-dilutive.

Share-Based Compensation (Tables)

6 Months Ended

Mar. 31, 2018

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity

The following table summarizes the Company's restricted stock awards ("RSAs") and restricted stock units ("RSUs") award activity for the period presented:



	Six Months Ended
	March 31, 2018
Restricted Stock Activity	Number of Shares		Weighted-Average Grant Date Fair Value
Balance, beginning of period	75,590		$	15.83
Granted	107,720		18.10
Vested	(53,355	)	15.50
Forfeited/canceled	(8,076	)	15.62
Balance, end of period	121,879		17.99

Schedule of Share-based Compensation, Stock Options, Activity

The following table summarizes the Company's stock option activity for the period presented:



	Six Months Ended
	March 31, 2018
Stock Option Award Activity	Number of Options		Weighted Average Exercise Price per Share ($)
Outstanding options, beginning of period	623,962		$	11.15
Granted	215,530		16.61
Exercised (1)	(73,102	)	12.27
Forfeited	(19,030	)	15.50
Outstanding options, end of period (2)	747,360		12.50
Fully vested and exercisable options, end of period (3)	535,302		10.87

(1) Stock options exercised in the period had an aggregate intrinsic value totaling $0.6 million.

(2) Stock options outstanding at the end of the period had an aggregate intrinsic value totaling $8.4 million.

(3) Fully vested and exercisable options at the end of the period had an aggregate intrinsic value totaling $6.9 million with a weighted average contractual remaining term of 7.3 years.

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions

The fair value of each option award at grant date was estimated using the Black-Scholes option-pricing model with the following assumptions and resulting grant-date fair value during the period presented:



	Six Months Ended
	March 31, 2018
Expected volatility	29.2		%
Expected dividend yield	0		%
Risk-free interest rate	2.16		%
Expected term (in years)	5.0 - 5.5
Weighted-average grant-date fair value	$	6.15

Accumulated Other Comprehensive Income (Tables)

6 Months Ended

Mar. 31, 2018

Equity [Abstract]

Schedule of Accumulated Other Comprehensive Income (Loss)

The following table provides information on changes in accumulated other comprehensive income (“AOCI”) for the periods presented:

Three Months Ended

Six Months Ended

(in thousands)

Defined Benefit Pension Plan

Cash Flow Hedges (Effective Portion)

Total AOCI

Defined Benefit Pension Plan

Cash Flow Hedges (Effective Portion)

Total AOCI

March 31, 2018

Balance, beginning of period