Consolidated Statements of Equity - USD ($) $ in Thousands	Total	Preferred stock	Common stock	Other paid-in capital	Retained earnings	Total accumulated other comprehensive loss	Treasury stock	Noncontrolling interest
Balance (in shares) at Dec. 31, 2016		150,000
Balance (in shares) at Dec. 31, 2015			195,804,665
Treasury stock (in shares) at Dec. 31, 2015							(538,921)
Balance at Dec. 31, 2015	$ 2,520,548	$ 15,000	$ 195,805	$ 1,230,119	$ 996,355	$ (37,148)	$ (3,626)	$ 124,043
Net income attributable to parent					64,433
Net loss attributable to noncontrolling interest								(131,691)
Net income (loss)	(67,258)
Other comprehensive income (loss)	1,415					1,415
Dividends declared on preferred stocks	(685)				(685)
Dividends declared on common stock	(147,821)				(147,821)
Stock-based compensation	4,383			4,383
Net tax deficit on stock-based compensation	(1,663)			(1,663)
Issuance of common stock (in shares)			38,632
Issuance of common stock			$ 38
Issuance of common stock upon vesting of stock-based compensation, net of shares used for tax withholdings				(361)
Issuance of common stock upon vesting of stock-based compensation, net of shares used for tax withholdings	(323)
Contribution from non-controlling interest	7,648							7,648
Redemption of preferred stock - premium	0
Redemption of preferred stock	0
Balance (in shares) at Dec. 31, 2015		150,000
Balance (in shares) at Dec. 31, 2016			195,843,297
Treasury stock (in shares) at Dec. 31, 2016							(538,921)
Balance at Dec. 31, 2016	2,316,244	$ 15,000	$ 195,843	1,232,478	912,282	(35,733)	$ (3,626)
Net income (loss)	281,203				281,203
Other comprehensive income (loss)	(1,601)					(1,601)
Dividends declared on preferred stocks	(171)				(171)
Dividends declared on common stock	(151,966)				(151,966)
Stock-based compensation	3,375			3,375
Repurchase of common stock (in shares)							(64,384)
Repurchase of common stock	(1,684)						$ (1,684)
Issuance of common stock upon vesting of stock-based compensation, net of shares used for tax withholdings				(2,441)
Issuance of common stock upon vesting of stock-based compensation, net of shares used for tax withholdings (in shares)							64,384
Issuance of common stock upon vesting of stock-based compensation, net of shares used for tax withholdings							$ 1,684
Issuance of common stock upon vesting of stock-based compensation, net of shares used for tax withholdings	(757)
Redemption of preferred stock (in shares)		(150,000)
Redemption of preferred stock - amount		$ (15,000)
Redemption of preferred stock - premium	(600)				(600)
Redemption of preferred stock	$ (15,600)
Balance (in shares) at Dec. 31, 2016		150,000
Balance (in shares) at Dec. 31, 2017	195,843,297		195,843,297
Treasury stock (in shares) at Dec. 31, 2017							(538,921)
Balance at Dec. 31, 2017	$ 2,429,043		$ 195,843	1,233,412	1,040,748	(37,334)	$ (3,626)
Cumulative effect of adoption of ASU 2014-09 | Accounting Standards Update 2014-09	(970)				(970)
Adjusted balance at January 1, 2018	2,428,073		$ 195,843	1,233,412	1,039,778	(37,334)	$ (3,626)
Net income (loss)	272,318				272,318
Other comprehensive income (loss)	6,951					6,951
Reclassification of certain prior period tax effects from accumulated other comprehensive loss | Adjustments for New Accounting Principle, Early Adoption	0				7,959	(7,959)
Dividends declared on common stock	(156,453)				(156,453)
Stock-based compensation	5,060			5,060
Repurchase of common stock (in shares)							(182,424)
Repurchase of common stock	(5,020)						$ (5,020)
Issuance of common stock (in shares)			721,610
Issuance of common stock	18,176		$ 722	17,454
Issuance of common stock upon vesting of stock-based compensation, net of shares used for tax withholdings				(7,350)
Issuance of common stock upon vesting of stock-based compensation, net of shares used for tax withholdings (in shares)							182,424
Issuance of common stock upon vesting of stock-based compensation, net of shares used for tax withholdings							$ 5,020
Issuance of common stock upon vesting of stock-based compensation, net of shares used for tax withholdings	(2,330)
Redemption of preferred stock - premium	0
Redemption of preferred stock	$ 0
Balance (in shares) at Dec. 31, 2018	196,564,907		196,564,907
Treasury stock (in shares) at Dec. 31, 2018							(538,921)
Balance at Dec. 31, 2018	$ 2,566,775		$ 196,565	$ 1,248,576	$ 1,163,602	$ (38,342)	$ (3,626)	$ 0