CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Thousands	Total	Preferred Shares [Member]	Common Shares [Member]	Additional Paid-in Capital [Member]	Accumulated Distributions in Excess of Net Income [Member]	Deferred Compensation Obligation [Member]	Accumulated Other Comprehensive (Loss) Income [Member]	Treasury Stock at Cost [Member]	Non-Controlling Interests [Member]
Beginning Balance at Dec. 31, 2020	$ 1,944,823	$ 325,000	$ 19,400	$ 5,705,164	$ (4,099,534)	$ 5,479	$ (2,682)	$ (11,319)	$ 3,315
Issuance of common shares related to stock plans	37		6	31
Issuance of common shares for cash offering	225,529		1,696	219,910				3,923
Stock-based compensation, net	10,621			8,580		(968)		3,009
Distributions to non-controlling interests	(16)								(16)
Dividends declared-common shares	(23,303)				(23,303)
Dividends declared-preferred shares	(4,950)				(4,950)
Comprehensive income	18,863				16,008		2,682		173
Ending Balance at Mar. 31, 2021	2,171,604	325,000	21,102	5,933,685	(4,111,779)	4,511		(4,387)	3,472
Beginning Balance at Dec. 31, 2020	1,944,823	325,000	19,400	5,705,164	(4,099,534)	5,479	(2,682)	(11,319)	3,315
Comprehensive income	40,850
Ending Balance at Jun. 30, 2021	2,017,031	175,000	21,104	5,940,528	(4,123,347)	4,484		(4,311)	3,573
Beginning Balance at Mar. 31, 2021	2,171,604	325,000	21,102	5,933,685	(4,111,779)	4,511		(4,387)	3,472
Issuance of common shares related to stock plans	62		2	60
Issuance of common shares for cash offering	(199)			(199)
Stock-based compensation, net	1,894			1,845		(27)		76
Distributions to non-controlling interests	(17)								(17)
Redemption of preferred shares	(150,019)	(150,000)		5,137	(5,156)
Dividends declared-common shares	(25,492)				(25,492)
Dividends declared-preferred shares	(2,789)				(2,789)
Comprehensive income	21,987				21,869				118
Ending Balance at Jun. 30, 2021	2,017,031	175,000	21,104	5,940,528	(4,123,347)	4,484		(4,311)	3,573
Beginning Balance at Dec. 31, 2021	2,042,652	175,000	21,129	5,934,166	(4,092,783)	4,695		(5,349)	5,794
Issuance of common shares related to stock plans	69	0	65	4	0	0		0	0
Issuance of common shares for cash offering	33,781	0	223	33,558	0	0
Stock-based compensation, net	(3,627)	0	0	996	0	(24)		(4,599)	0
Distributions to non-controlling interests	(18)	0	0	0	0	0		0	(18)
Dividends declared-common shares	(27,905)	0	0	0	(27,905)	0		0	0
Dividends declared-preferred shares	(2,789)	0	0	0	(2,789)	0		0	0
Comprehensive income	13,955	0	0	0	13,937	0		0	18
Ending Balance at Mar. 31, 2022	2,056,118	175,000	21,417	5,968,724	(4,109,540)	4,671		(9,948)	5,794
Beginning Balance at Dec. 31, 2021	2,042,652	175,000	21,129	5,934,166	(4,092,783)	4,695		(5,349)	5,794
Comprehensive income	74,364
Ending Balance at Jun. 30, 2022	2,090,678	175,000	21,437	5,973,435	(4,079,844)	4,703		(9,847)	5,794
Beginning Balance at Mar. 31, 2022	2,056,118	175,000	21,417	5,968,724	(4,109,540)	4,671		(9,948)	5,794
Issuance of common shares related to stock plans	2	0	0	2	0	0		0	0
Issuance of common shares for cash offering	3,076	0	20	3,056	0	0		0	0
Stock-based compensation, net	1,786	0	0	1,653	0	32		101	0
Distributions to non-controlling interests	(19)	0	0	0	0	0		0	(19)
Dividends declared-common shares	(27,905)	0	0	0	(27,905)	0		0	0
Dividends declared-preferred shares	(2,789)	0	0	0	(2,789)	0		0	0
Comprehensive income	60,409	0	0	0	60,390	0		0	19
Ending Balance at Jun. 30, 2022	$ 2,090,678	$ 175,000	$ 21,437	$ 5,973,435	$ (4,079,844)	$ 4,703		$ (9,847)	$ 5,794