CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Shares	Cumulative Common Distributions	Additional Paid in Capital	Cumulative Net Income	Cumulative Other Comprehensive Income (Loss)
Beginning balance (in shares) at Dec. 31, 2018		164,441,709
Beginning balance at Dec. 31, 2018	$ 2,597,431	$ 1,644	$ (5,181,323)	$ 4,545,481	$ 3,231,895	$ (266)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	259,750				259,750
Amounts reclassified from cumulative other comprehensive income to net income	175					175
Equity in unrealized gains (losses) of investees	91					91
Common share grants (in shares)		155,100
Common share grants	$ 2,857	$ 2		2,855
Common share repurchases (in shares)	(31,225)	(33,775)
Common share repurchases	$ (807)			(807)
Distributions	(353,619)		(353,619)
Ending balance (in shares) at Dec. 31, 2019		164,563,034
Ending balance at Dec. 31, 2019	2,505,878	$ 1,646	(5,534,942)	4,547,529	3,491,645	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(311,382)				(311,382)
Amounts reclassified from cumulative other comprehensive income to net income	0
Equity in unrealized gains (losses) of investees	(760)					(760)
Common share grants (in shares)		305,400
Common share grants	$ 3,211	$ 2		3,209
Common share repurchases (in shares)	(43,751)
Common share repurchases and forfeitures (in shares)		(44,601)
Common share repurchases and forfeitures	$ (353)			(353)
Distributions	(93,804)		(93,804)
Ending balance (in shares) at Dec. 31, 2020		164,823,833
Ending balance at Dec. 31, 2020	2,102,790	$ 1,648	(5,628,746)	4,550,385	3,180,263	(760)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(544,603)				(544,603)
Amounts reclassified from cumulative other comprehensive income to net income	0
Equity in unrealized gains (losses) of investees	1,539					1,539
Common share grants (in shares)		340,700
Common share grants	$ 2,967	$ 3		2,964
Common share repurchases (in shares)	(71,100)
Common share repurchases and forfeitures (in shares)		(72,200)
Common share repurchases and forfeitures	$ (791)			(791)
Distributions	(6,596)		(6,596)
Ending balance (in shares) at Dec. 31, 2021		165,092,333
Ending balance at Dec. 31, 2021	$ 1,555,306	$ 1,651	$ (5,635,342)	$ 4,552,558	$ 2,635,660	$ 779