CONSOLIDATED STATEMENTS OF BENEFICIARIES’ EQUITY - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Deferred Compensation Payable in Common Shares	Additional Paid-in Capital	Common Shares in Grantor Trust	Cumulative Earnings	Cumulative Earnings Cumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive Income (Loss)	Cumulative Distributions	Noncontrolling Interests
Beginning balance (in shares) at Dec. 31, 2018			176,873,324	977,120
Beneficiaries' Equity, beginning balance at Dec. 31, 2018	$ 1,811,028	$ (5,336)	$ 1,770	$ 14,021	$ 3,200,312	$ (14,021)	$ 775,625	$ (5,336)	$ 5,029	$ (2,183,909)	$ 12,201
Parent Company
Net income	34,529						34,267				262
Other comprehensive income	$ (7,440)								(7,399)		(41)
Repurchase and retirement of Common Shares of Beneficial Interest (in shares)	(1,337,169)		(1,337,169)
Repurchase and retirement of Common Shares of Beneficial Interest	$ (17,281)		$ (13)		(17,268)
Issuance of partnership interest in consolidated real estate venture	27										27
Purchase of partnership interest in consolidated real estate venture	(2,180)				(983)						(1,197)
Redemption of LP Units (in shares)			1,245
Redemption of LP Units	0				16						(16)
Share-based compensation activity (in shares)			845,210	41,342
Share-based compensation activity	10,027		$ 9		10,018
Share Issuance from/(to) Deferred Compensation Plan (in shares)			97,485	87,080
Share Issuance from/(to) Deferred Compensation Plan	0			$ 2,195		(2,195)
Reallocation of Noncontrolling Interest	0				63						(63)
Distributions declared	(135,071)									(134,324)	(747)
Ending balance (in shares) at Dec. 31, 2019			176,480,095	1,105,542
Beneficiaries' Equity, ending balance at Dec. 31, 2019	1,688,303		$ 1,766	$ 16,216	3,192,158	(16,216)	804,556		(2,370)	(2,318,233)	10,426
Parent Company
Net income	307,326						305,527				1,799
Other comprehensive income	$ (5,220)								(5,191)		(29)
Repurchase and retirement of Common Shares of Beneficial Interest (in shares)	(6,248,483)		(6,248,483)
Repurchase and retirement of Common Shares of Beneficial Interest	$ (59,999)		$ (62)		(59,937)
Sale of partnership interest to consolidated real estate venture	(1,017)										(1,017)
Distributions from consolidated real estate venture	(22)										(22)
Share-based compensation activity (in shares)			309,096	50,967
Share-based compensation activity	6,236		$ 3		6,233
Share Issuance from/(to) Deferred Compensation Plan (in shares)			32,256	3,985
Share Issuance from/(to) Deferred Compensation Plan	(206)			$ 1,300	(206)	(1,300)
Reallocation of Noncontrolling Interest	0				(96)						96
Distributions declared	(130,753)									(130,005)	(748)
Ending balance (in shares) at Dec. 31, 2020			170,572,964	1,160,494
Beneficiaries' Equity, ending 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
Parent Company
Net income	12,366						12,289				77
Other comprehensive income	5,569								5,541		28
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 venture	2,765										2,765
Redemption of LP Units	(2,334)										(2,334)
Share-based compensation activity (in shares)			344,656	70,645
Share-based compensation activity	6,354		$ 2		6,352
Share Issuance from/(to) Deferred Compensation Plan (in shares)			(18,058)	(61,436)
Share Issuance from/(to) Deferred Compensation Plan	(198)			$ 975	(198)	(975)
Reallocation of Noncontrolling Interest	0				(569)						569
Distributions declared	(131,003)									(130,345)	(658)
Ending balance (in shares) at Dec. 31, 2021			171,126,257	1,169,703
Beneficiaries' Equity, ending 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