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 Income [Member]	Treasury Stock at Cost [Member]	Non-Controlling Interests [Member]
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			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
Beginning Balance at Dec. 31, 2022	2,092,622	175,000	21,437	5,974,216	(4,046,370)	5,025	$ 9,038	(51,518)	5,794
Issuance of common shares related to stock plans	6	0	0	6	0	0	0	0	0
Repurchase of common shares	(26,611)	0	0	0	0	0	0	(26,611)	0
Stock-based compensation, net	(3,009)	0	0	(8,133)	0	30	0	5,094	0
Distributions to non-controlling interests	(18)	0	0	0	0	0	0	0	(18)
Dividends declared-common shares	(27,292)	0	0	0	(27,292)	0	0	0	0
Dividends declared-preferred shares	(2,789)	0	0	0	(2,789)	0	0	0	0
Comprehensive income	12,102	0	0	0	15,284	0	(3,200)	0	18
Ending Balance at Mar. 31, 2023	2,045,011	175,000	21,437	5,966,089	(4,061,167)	5,055	5,838	(73,035)	5,794
Beginning Balance at Dec. 31, 2022	2,092,622	175,000	21,437	5,974,216	(4,046,370)	5,025	9,038	(51,518)	5,794
Comprehensive income	21,742
Ending Balance at Jun. 30, 2023	2,024,698	175,000	21,437	5,971,918	(4,085,897)	4,941	10,125	(72,826)	0
Beginning Balance at Mar. 31, 2023	2,045,011	175,000	21,437	5,966,089	(4,061,167)	5,055	5,838	(73,035)	5,794
Issuance of common shares related to stock plans	7	0	0	7	0	0	0	0	0
Stock-based compensation, net	1,858	0	0	1,763	0	(114)	0	209	0
Repurchase of OP units	(1,735)	0	0	4,059	0	0	0	0	(5,794)
Dividends declared-common shares	(27,294)	0	0	0	(27,294)	0	0	0	0
Dividends declared-preferred shares	(2,789)	0	0	0	(2,789)	0	0	0	0
Comprehensive income	9,640	0	0	0	5,353	0	4,287	0	0
Ending Balance at Jun. 30, 2023	$ 2,024,698	$ 175,000	$ 21,437	$ 5,971,918	$ (4,085,897)	$ 4,941	$ 10,125	$ (72,826)	$ 0