Cover page. [Abstract] Cover page. [Abstract] Document Information [Table] Document Information [Table] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Common Stock, $0.01 par value Common Stock [Member] 6.875% Series C Preferred Stock, $0.01 par value Series C Preferred Stock [Member] 6.125% Series D Preferred Stock, $0.01 par value Series D Preferred Stock [Member] Document Information [Line Items] Document Information [Line Items] Document Type Document Type Document Period End Date Document Period End Date Entity Registrant Name Entity Registrant Name Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Entity File Number Entity File Number Entity Tax Identification Number Entity Tax Identification Number Entity Address, Address Line One Entity Address, Address Line One Entity Address, City or Town Entity Address, City or Town Entity Address, State or Province Entity Address, State or Province Entity Address, Postal Zip Code Entity Address, Postal Zip Code City Area Code City Area Code Local Phone Number Local Phone Number Written Communications Written Communications Soliciting Material Soliciting Material Pre-commencement Tender Offer Pre-commencement Tender Offer Pre-commencement Issuer Tender Offer Pre-commencement Issuer Tender Offer Entity Emerging Growth Company Entity Emerging Growth Company Title of 12(b) Security Title of 12(b) Security Security Exchange Name Security Exchange Name Trading Symbol Trading Symbol Entity Central Index Key Entity Central Index Key Amendment Flag Amendment Flag