Consolidated Statements of Equity - USD ($) $ in Thousands	Total	Cumulative effect of changes in accounting standards	Total Shareholders’ Equity	Total Shareholders’ Equity Cumulative effect of changes in accounting standards	Par Value	Additional Paid in Capital	Additional Paid in Capital Cumulative effect of changes in accounting standards	Accumulated Deficit	Accumulated Other Comprehensive (Loss) Income	Total  Noncontrolling Interests	Operating Partnership Noncontrolling interest	Partially Owned Properties Noncontrolling Interest
Shareholders' equity, beginning balance at Dec. 31, 2018	$ 2,447,660	$ (239)	$ 2,379,505	$ (239)	$ 1,824	$ 2,791,555	$ (239)	$ (428,307)	$ 14,433	$ 68,155	$ 67,477	$ 678
Increase (Decrease) in Stockholders' Equity
Net proceeds from sale of common shares	131,629		131,629		74	131,555
Restricted share award grants, net	7,022		7,022		2	7,918		(898)
Purchase of OP Units	(14,023)									(14,023)	(14,023)
Dividends/distributions declared	(177,271)		(172,324)					(172,324)		(4,947)	(4,947)
Preferred distributions	(1,209)		(1,209)					(1,209)
Issuance of OP Units in connection with acquisition	22,598									22,598	22,598
Contributions	572									572		572
Distributions	(174)									(174)		(174)
Change in market value of Redeemable Noncontrolling Interest in Operating Partnership	(1,248)		(1,248)			(309)		(939)
Buyout of Noncontrolling Interest - partially owned properties	(1,112)		(122)			(122)				(990)		(990)
Derecognition of cash flow hedge	0
Change in fair value of interest rate swap agreements	(10,112)		(10,112)						(10,112)
Adjustment for Noncontrolling Interests ownership in Operating Partnership	0		1,563			1,563				(1,563)	(1,563)
Net income	76,891		74,483					74,483		2,408	2,155	253
Shareholders' equity, ending balance at Dec. 31, 2019	2,480,984	$ (147)	2,408,948	$ (147)	1,900	2,931,921	$ (147)	(529,194)	4,321	72,036	71,697	339
Increase (Decrease) in Stockholders' Equity
Net proceeds from sale of common shares	364,388		364,388		194	364,194
Restricted share award grants, net	7,729		7,729		2	9,510		(1,783)
Purchase of OP Units	(515)									(515)	(515)
Conversion of OP Units	0		41			41				(41)	(41)
Dividends/distributions declared	(195,874)		(190,751)					(190,751)		(5,123)	(5,123)
Preferred distributions	(1,241)		(1,241)					(1,241)
Issuance of OP Units in connection with acquisition	3,067									3,067	3,067
Distributions	(210)									(210)		(210)
Change in market value of Redeemable Noncontrolling Interest in Operating Partnership	(1,187)		(1,187)			132		(1,319)
Derecognition of cash flow hedge	0
Change in fair value of interest rate swap agreements	(10,180)		(10,180)						(10,180)
Adjustment for Noncontrolling Interests ownership in Operating Partnership	0		(2,420)			(2,420)				2,420	2,420
Net income	68,188		66,117					66,117		2,071	1,797	274
Shareholders' equity, ending balance at Dec. 31, 2020	2,715,002		2,641,297		2,096	3,303,231		(658,171)	(5,859)	73,705	73,302	403
Increase (Decrease) in Stockholders' Equity
Net proceeds from sale of common shares	268,126		268,126		147	267,979
Restricted share award grants, net	9,414		9,414		4	10,722		(1,312)
Purchase of OP Units	(6,237)									(6,237)	(6,237)
Dividends/distributions declared	(207,383)		(200,926)					(200,926)		(6,457)	(6,457)
Preferred distributions	(13)		(13)					(13)
Issuance of OP Units in connection with acquisition	116,467									116,467	116,467
Distributions	(224)									(224)		(224)
Change in market value of Redeemable Noncontrolling Interest in Operating Partnership	433		433			(23)		456
Derecognition of cash flow hedge	3,295		3,295						3,295
Change in fair value of interest rate swap agreements	1,672		1,672						1,672
Adjustment for Noncontrolling Interests ownership in Operating Partnership	0		29,045			29,045				(29,045)	(29,045)
Net income	86,481		83,965					83,965		2,516	2,211	305
Shareholders' equity, ending balance at Dec. 31, 2021	$ 2,987,033		$ 2,836,308		$ 2,247	$ 3,610,954		$ (776,001)	$ (892)	$ 150,725	$ 150,241	$ 484