CONSOLIDATED STATEMENTS OF BENEFICIARIES’ EQUITY - USD ($) $ in Thousands	Total	Common Stock	Rabbi Trust/Deferred Compensation Shares	Additional Paid-in Capital	Common Shares in Grantor Trust	Cumulative Earnings	Accumulated Other Comprehensive Income (Loss)	Cumulative Distributions	Noncontrolling Interests
Beginning balance (in shares) at Dec. 31, 2020		170,572,964	1,160,494
Beginning balance at Dec. 31, 2020	$ 1,804,648	$ 1,707	$ 17,516	$ 3,138,152	$ (17,516)	$ 1,110,083	$ (7,561)	$ (2,448,238)	$ 10,505
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	6,964					6,921			43
Other comprehensive income	1,098						1,092		6
Share-based compensation activity (in shares)		108,345	12,719
Share-based compensation activity	2,502			2,502
Share Issuance from/(to) Deferred Compensation Plan (in shares)		(18,058)	(61,436)
Share Issuance from/(to) Deferred Compensation Plan	(198)		$ 142	(198)	(142)
Distributions declared	(32,760)							(32,573)	(187)
Ending balance (in shares) at Mar. 31, 2021		170,663,251	1,111,777
Ending balance at Mar. 31, 2021	1,782,254	$ 1,707	$ 17,658	3,140,456	(17,658)	1,117,004	(6,469)	(2,480,811)	10,367
Beginning balance (in shares) at Dec. 31, 2020		170,572,964	1,160,494
Beginning balance at Dec. 31, 2020	1,804,648	$ 1,707	$ 17,516	3,138,152	(17,516)	1,110,083	(7,561)	(2,448,238)	10,505
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	7,763
Other comprehensive income	3,245
Ending balance (in shares) at Sep. 30, 2021		171,126,257	1,169,703
Ending balance at Sep. 30, 2021	1,725,477	$ 1,712	$ 18,491	3,145,209	(18,491)	1,117,804	(4,333)	(2,545,979)	11,064
Beginning balance (in shares) at Mar. 31, 2021		170,663,251	1,111,777
Beginning balance at Mar. 31, 2021	1,782,254	$ 1,707	$ 17,658	3,140,456	(17,658)	1,117,004	(6,469)	(2,480,811)	10,367
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	(175)					(167)			(8)
Other comprehensive income	1,048						1,042		6
Issuance of partnership interest in consolidated real estate ventures	2,289								2,289
Redemption of LP Units	(2,334)								(2,334)
Share-based compensation activity (in shares)		237,240	63,566
Share-based compensation activity	690	$ 2		688
Share Issuance from/(to) Deferred Compensation Plan	0		$ 833		(833)
Reallocation of Noncontrolling interest	0			(569)					569
Distributions declared	(32,719)							(32,562)	(157)
Ending balance (in shares) at Jun. 30, 2021		170,900,491	1,175,343
Ending balance at Jun. 30, 2021	1,751,053	$ 1,709	$ 18,491	3,140,575	(18,491)	1,116,837	(5,427)	(2,513,373)	10,732
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	974					967			7
Other comprehensive income	1,099						1,094		5
Issuance of Common Shares of Beneficial Interest (in shares)		226,695
Issuance of Common Shares of Beneficial Interest	3,052	$ 3		3,049
Issuance of partnership interest in consolidated real estate ventures	476								476
Share-based compensation activity (in shares)		(929)	(5,640)
Share-based compensation activity	1,585			1,585
Distributions declared	(32,762)							(32,606)	(156)
Ending balance (in shares) at Sep. 30, 2021		171,126,257	1,169,703
Ending balance at Sep. 30, 2021	$ 1,725,477	$ 1,712	$ 18,491	3,145,209	(18,491)	1,117,804	(4,333)	(2,545,979)	11,064
Beginning balance (in shares) at Dec. 31, 2021	171,126,257	171,126,257	1,169,703
Beginning balance at Dec. 31, 2021	$ 1,701,219	$ 1,712	$ 18,491	3,146,786	(18,491)	1,122,372	(2,020)	(2,578,583)	10,952
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	6,101					6,093			8
Other comprehensive income	3,952						3,940		12
Redemption of LP Units	(4,006)								(4,006)
Share-based compensation activity (in shares)		277,061	68,540
Share-based compensation activity	1,655	$ 2		1,653
Share Issuance from/(to) Deferred Compensation Plan (in shares)		(19,406)	(52,702)
Share Issuance from/(to) Deferred Compensation Plan	(249)		$ 895	(249)	(895)
Reallocation of Noncontrolling interest	0			(959)					959
Distributions declared	(32,809)							(32,711)	(98)
Ending balance (in shares) at Mar. 31, 2022		171,383,912	1,185,541
Ending balance at Mar. 31, 2022	$ 1,675,863	$ 1,714	$ 19,386	3,147,231	(19,386)	1,128,465	1,920	(2,611,294)	7,827
Beginning balance (in shares) at Dec. 31, 2021	171,126,257	171,126,257	1,169,703
Beginning balance at Dec. 31, 2021	$ 1,701,219	$ 1,712	$ 18,491	3,146,786	(18,491)	1,122,372	(2,020)	(2,578,583)	10,952
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	24,230
Other comprehensive income	$ 6,565
Ending balance (in shares) at Sep. 30, 2022	171,569,807	171,569,807	1,179,643
Ending balance at Sep. 30, 2022	$ 1,634,949	$ 1,716	$ 19,601	3,151,177	(19,601)	1,146,543	4,525	(2,676,702)	7,690
Beginning balance (in shares) at Mar. 31, 2022		171,383,912	1,185,541
Beginning balance at Mar. 31, 2022	1,675,863	$ 1,714	$ 19,386	3,147,231	(19,386)	1,128,465	1,920	(2,611,294)	7,827
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	4,651					4,637			14
Other comprehensive income	1,935						1,929		6
Share-based compensation activity (in shares)		191,368	16,844
Share-based compensation activity	1,917	$ 2		1,915
Share Issuance from/(to) Deferred Compensation Plan (in shares)
Share Issuance from/(to) Deferred Compensation Plan	0		$ 215		(215)
Distributions declared	(32,803)							(32,705)	(98)
Ending balance (in shares) at Jun. 30, 2022		171,575,280	1,202,385
Ending balance at Jun. 30, 2022	1,651,563	$ 1,716	$ 19,601	3,149,146	(19,601)	1,133,102	3,849	(2,643,999)	7,749
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	13,478					13,441			37
Other comprehensive income	678						676		2
Share-based compensation activity (in shares)		1,100
Share-based compensation activity	2,094			2,094
Share Issuance from/(to) Deferred Compensation Plan (in shares)		(6,573)	(22,742)
Share Issuance from/(to) Deferred Compensation Plan	(63)			(63)
Distributions declared	$ (32,801)							(32,703)	(98)
Ending balance (in shares) at Sep. 30, 2022	171,569,807	171,569,807	1,179,643
Ending balance at Sep. 30, 2022	$ 1,634,949	$ 1,716	$ 19,601	$ 3,151,177	$ (19,601)	$ 1,146,543	$ 4,525	$ (2,676,702)	$ 7,690