Consolidated Statements of Changes in Equity - USD ($) $ in Thousands	Total	Common Stock	Paid-in Capital	Redeemable Perpetual Preferred Stock	Distributions in Excess of Accumulated Earnings	Accumulated Other Comprehensive Income (Loss)	Non-controlling Interests – Common OP Units
Beginning balance at Dec. 31, 2020	$ 1,304,755	$ 1,813	$ 1,411,397	$ 0	$ (179,523)	$ 0	$ 71,068
Increase (Decrease) in Stockholders' Equity
Exchange of Common OP Units for Common Stock	0		58				(58)
Issuance of Common Stock through employee stock purchase plan	732		732
Compensation expenses related to restricted stock and stock options	2,556		2,556
Repurchase of Common Stock or Common OP Units	(2,814)		(2,814)
Adjustment for fair market value of swap	129					129
Consolidated net income	68,987				65,240		3,747
Distributions	(69,883)				(66,087)		(3,796)
Other	(116)		(116)
Ending balance at Mar. 31, 2021	1,304,346	1,813	1,411,813	0	(180,370)	129	70,961
Beginning balance at Dec. 31, 2020	1,304,755	1,813	1,411,397	0	(179,523)	0	71,068
Increase (Decrease) in Stockholders' Equity
Adjustment for fair market value of swap	239
Ending balance at Jun. 30, 2021	1,301,991	1,827	1,424,350	0	(185,930)	239	61,505
Beginning balance at Mar. 31, 2021	1,304,346	1,813	1,411,813	0	(180,370)	129	70,961
Increase (Decrease) in Stockholders' Equity
Exchange of Common OP Units for Common Stock	0	14	9,310				(9,324)
Issuance of Common Stock through employee stock purchase plan	605		605
Compensation expenses related to restricted stock and stock options	2,821		2,821
Adjustment for Common OP Unitholders in the Operating Partnership	0		(143)				143
Adjustment for fair market value of swap	110					110
Consolidated net income	64,080			8	61,051		3,021
Distributions	(69,915)			(8)	(66,611)		(3,296)
Other	(56)		(56)
Ending balance at Jun. 30, 2021	1,301,991	1,827	1,424,350	0	(185,930)	239	61,505
Beginning balance at Dec. 31, 2021	1,486,171	1,913	1,593,362	0	(183,689)	3,524	71,061
Increase (Decrease) in Stockholders' Equity
Exchange of Common OP Units for Common Stock	0		67				(67)
Issuance of Common Stock through employee stock purchase plan	513		513
Issuance of Common Stock	28,370	3	28,367
Compensation expenses related to restricted stock and stock options	2,590		2,590
Repurchase of Common Stock or Common OP Units	(3,449)		(3,449)
Adjustment for Common OP Unitholders in the Operating Partnership	0		(1,641)				1,641
Adjustment for fair market value of swap	9,924					9,924
Consolidated net income	87,050				82,906		4,144
Distributions	(80,187)				(76,375)		(3,812)
Other	(645)		(645)
Ending balance at Mar. 31, 2022	1,530,337	1,916	1,619,164	0	(177,158)	13,448	72,967
Beginning balance at Dec. 31, 2021	1,486,171	1,913	1,593,362	0	(183,689)	3,524	71,061
Increase (Decrease) in Stockholders' Equity
Adjustment for fair market value of swap	12,717
Ending balance at Jun. 30, 2022	1,521,736	1,916	1,622,876	0	(191,828)	16,241	72,531
Beginning balance at Mar. 31, 2022	1,530,337	1,916	1,619,164	0	(177,158)	13,448	72,967
Increase (Decrease) in Stockholders' Equity
Issuance of Common Stock through employee stock purchase plan	1,388		1,388
Compensation expenses related to restricted stock and stock options	2,681		2,681
Adjustment for Common OP Unitholders in the Operating Partnership	0		(303)				303
Adjustment for fair market value of swap	2,793					2,793
Consolidated net income	64,590			8	61,509		3,073
Distributions	(79,999)			(8)	(76,179)		(3,812)
Other	(54)		(54)
Ending balance at Jun. 30, 2022	$ 1,521,736	$ 1,916	$ 1,622,876	$ 0	$ (191,828)	$ 16,241	$ 72,531