Condensed Consolidated Statements of Shareholders' Deficit (unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Distributions in Excess of Accumulated Earnings	Noncontrolling Interest
Beginning balance, value at Dec. 31, 2016	$ (1,402,445)	$ 15	$ 141,092	$ (6,369)	$ (1,537,183)
Beginning balance, shares at Dec. 31, 2016		155,138,637
Net income (loss)	(20,000)				(20,000)
Amortization of discount on convertible preferred stock	(745)		(745)
Other comprehensive income	9,441			9,441
Common stock dividends	(93,692)				(93,692)
Convertible preferred stock dividends	(656)				(656)
Equity issuance cost	(54)		(54)
Net share settlement	(1,690)		(421)		(1,269)
Stock-based compensation	1,632	$ 1	1,631
Stock-based compensation, shares		136,866
Ending balance, value at Mar. 31, 2017	(1,508,209)	$ 16	141,503	3,072	(1,652,800)
Ending balance, shares at Mar. 31, 2017		155,275,503
Beginning balance, value at Dec. 31, 2017	(1,207,142)	$ 17	644,328	7,821	(1,960,715)	$ 101,407
Beginning balance, shares at Dec. 31, 2017		174,851,514
Net income (loss)	1,231				1,210	21
Amortization of discount on convertible preferred stock	(745)		(745)
Other comprehensive income	39,833			38,914		919
Common stock dividends	(105,069)				(105,069)
Distributions to noncontrolling interest	(2,479)					(2,479)
Convertible preferred stock dividends	(656)				(656)
Net share settlement	(659)		(390)		(269)
Stock-based compensation	2,210		2,210
Stock-based compensation, shares		118,132
Impact of change in accounting standard	1,859				1,859
Ending balance, value at Mar. 31, 2018	$ (1,271,617)	$ 17	$ 645,403	$ 46,735	$ (2,063,640)	$ 99,868
Ending balance, shares at Mar. 31, 2018		174,969,646