CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) $ in Thousands	Total	Preferred Shares	Common Shares	Additional Paid-in-Capital	Accumulated Distributions in Excess of Net Income	Accumulated Other Comprehensive Loss	Noncontrolling Interests
Beginning Balance at Dec. 31, 2019	$ 1,724,719	$ 94,016	$ 25	$ 2,976,670	$ (1,363,676)	$ (1,928)	$ 19,612
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of partnership interest in real estate	887						887
Redemption of noncontrolling OP units for common shares				482			(482)
Issuance of common shares and deferred compensation amortization, net	221,974		3	221,971
Repurchase of common shares to settle tax obligations	(2,623)		0	(2,623)
Forfeiture of employee common shares	1				1
Dividends/distributions	(60,479)				(59,346)		(1,133)
Net income	37,551				37,020		531
Other comprehensive loss	(18,802)					(18,802)
Repurchase of common shares	(11,042)			(11,042)
Ending Balance at Jun. 30, 2020	1,892,186	94,016	28	3,185,458	(1,386,001)	(20,730)	19,415
Beginning Balance at Mar. 31, 2020	1,702,670	94,016	26	2,982,363	(1,374,286)	(18,924)	19,475
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of partnership interest in real estate	466						466
Redemption of noncontrolling OP units for common shares				54			(54)
Issuance of common shares and deferred compensation amortization, net	203,043		2	203,041
Dividends/distributions	(31,318)				(30,581)		(737)
Net income	19,131				18,866		265
Other comprehensive loss	(1,806)					(1,806)
Ending Balance at Jun. 30, 2020	1,892,186	94,016	28	3,185,458	(1,386,001)	(20,730)	19,415
Beginning Balance at Dec. 31, 2020	1,991,137	94,016	28	3,196,315	(1,301,726)	(17,963)	20,467
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of partnership interest in real estate	5,085						5,085
Redemption of noncontrolling OP units for common shares				468			(468)
Issuance of common shares and deferred compensation amortization, net	2,942		0	2,942
Repurchase of common shares to settle tax obligations	(5,120)			(5,120)
Forfeiture of employee common shares	2			0	2
Dividends/distributions	(63,861)				(62,731)		(1,130)
Net income	115,262				113,720		1,542
Other comprehensive loss	5,922					5,922
Reallocation of noncontrolling interests				435			(435)
Ending Balance at Jun. 30, 2021	2,051,369	94,016	28	3,195,040	(1,250,735)	(12,041)	25,061
Beginning Balance at Mar. 31, 2021	2,005,326	94,016	28	3,193,023	(1,292,051)	(12,617)	22,927
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of partnership interest in real estate	2,373						2,373
Redemption of noncontrolling OP units for common shares				157			(157)
Issuance of common shares and deferred compensation amortization, net	1,425			1,425
Dividends/distributions	(32,118)				(31,362)		(756)
Net income	73,787				72,678		1,109
Other comprehensive loss	576					576
Reallocation of noncontrolling interests				435			(435)
Ending Balance at Jun. 30, 2021	$ 2,051,369	$ 94,016	$ 28	$ 3,195,040	$ (1,250,735)	$ (12,041)	$ 25,061