Cover page. [Abstract] Cover page. [Abstract] Entities [Table] Entities [Table] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Class A Common Stock, $0.01 par value Common Class A [Member] Preferred Stock, 8.25% Series B Cumulative Redeemable, $0.01 par value Series B [Member] Preferred Stock, 8.75% Series E Cumulative Redeemable, $0.01 par value Series E Preferred Stock [Member] Preferred Stock, 7.50% Series G Cumulative Redeemable, $0.01 par value Series G Preferred Stock [Member] Preferred Stock, 7.125% Series H Cumulative Redeemable, $0.01 par value Series H Preferred Stock [Member] Preferred Stock, 7.15% Series I Cumulative Redeemable, $0.01 par value Series I Preferred Stock [Member] Series I Preferred Stock Preferred Stock, 7.125% Series J Cumulative Redeemable, $0.01 par value Series J Preferred Stock [Member] Series J Preferred Stock [Member] Entity Information [Line Items] Entity Information [Line Items] Entity Central Index Key Entity Central Index Key Entity Emerging Growth Company Entity Emerging Growth Company Title of 12(b) Security Title of 12(b) Security Trading Symbol Trading Symbol Security Exchange Name Security Exchange Name Written Communications Written Communications Entity Address, Address Line One Entity Address, Address Line One Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Entity Registrant Name Entity Registrant Name Document Type Document Type Document Period End Date Document Period End Date Entity File Number Entity File Number Entity Tax Identification Number Entity Tax Identification Number Entity Address, Address Line Two Entity Address, Address Line Two Entity Address, Postal Zip Code Entity Address, Postal Zip Code Entity Address, City or Town Entity Address, City or Town Entity Address, State or Province Entity Address, State or Province City Area Code City Area Code Local Phone Number Local Phone Number Soliciting Material Soliciting Material Pre-commencement Tender Offer Pre-commencement Tender Offer Pre-commencement Issuer Tender Offer Pre-commencement Issuer Tender Offer Amendment Flag Amendment Flag