CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - Unaudited - USD ($) $ in Thousands	Total	Common Shares	Additional Paid-in Capital	Distributions In Excess Of Earnings	Accumulated Other Comprehensive Income / (Loss)	Noncontrolling Interest in Joint Ventures
BALANCE at Dec. 31, 2019	$ 1,202,329	$ 4	$ 1,514,055	$ (316,302)	$ 2,807	$ 1,765
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	23,298	0	0	23,297	0	1
Net unrealized change in fair value of interest rate swaps	(15,790)	0	0	0	(15,790)	0
Common dividends declared	(29,366)	0	0	(29,366)	0	0
Stock-based compensation, net of forfeitures	1,781	0	1,781	0	0	0
Issuance of common stock, common stock offering, net of expenses	14,734	0	14,734	0	0	0
Withheld shares of common stock to satisfy tax withholding obligations in connection with the vesting of restricted stock	(4,589)	0	(4,589)	0	0	0
Distributions to noncontrolling interest	(34)	0	0	0	0	(34)
BALANCE at Mar. 31, 2020	$ 1,192,363	4	1,525,981	(322,371)	(12,983)	1,732
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common dividends declared - per share (in dollars per share)	$ 0.75
Issuance of shares of common stock, common stock offering, net of expenses	105,837
Withheld shares of common stock to satisfy tax withholding obligations in connection with vesting of restricted stock shares	33,963
BALANCE at Dec. 31, 2019	$ 1,202,329	4	1,514,055	(316,302)	2,807	1,765
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	71,196
Net unrealized change in fair value of interest rate swaps	(16,252)
BALANCE at Sep. 30, 2020	1,244,618	4	1,591,720	(335,359)	(13,445)	1,698
BALANCE at Mar. 31, 2020	1,192,363	4	1,525,981	(322,371)	(12,983)	1,732
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	23,487	0	0	23,484	0	3
Net unrealized change in fair value of interest rate swaps	(1,824)	0	0	0	(1,824)	0
Common dividends declared	(29,551)	0	0	(29,551)	0	0
Stock-based compensation, net of forfeitures	2,694	0	2,694	0	0	0
Issuance of common stock, common stock offering, net of expenses	29,647	0	29,647	0	0	0
Distributions to noncontrolling interest	(19)	0	0	0	0	(19)
BALANCE at Jun. 30, 2020	$ 1,216,797	4	1,558,322	(328,438)	(14,807)	1,716
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common dividends declared - per share (in dollars per share)	$ 0.75
Issuance of shares of common stock, common stock offering, net of expenses	243,621
Net Income	$ 24,411	0	0	24,401	0	10
Net unrealized change in fair value of interest rate swaps	1,362	0	0	0	1,362	0
Common dividends declared	(31,322)	0	0	(31,322)	0	0
Stock-based compensation, net of forfeitures	2,036	0	2,036	0	0	0
Issuance of common stock, common stock offering, net of expenses	31,362	0	31,362	0	0	0
Distributions to noncontrolling interest	(28)	0	0	0	0	(28)
BALANCE at Sep. 30, 2020	$ 1,244,618	4	1,591,720	(335,359)	(13,445)	1,698
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common dividends declared - per share (in dollars per share)	$ 0.79
Issuance of shares of common stock, common stock offering, net of expenses	238,086
BALANCE at Dec. 31, 2020	$ 1,270,518	4	1,610,053	(329,667)	(10,752)	880
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	27,357	0	0	27,339	0	18
Net unrealized change in fair value of interest rate swaps	8,214	0	0	0	8,214	0
Common dividends declared	(31,672)	0	0	(31,672)	0	0
Stock-based compensation, net of forfeitures	2,147	0	2,147	0	0	0
Issuance of common stock, common stock offering, net of expenses	44,485	0	44,485	0	0	0
Withheld shares of common stock to satisfy tax withholding obligations in connection with the vesting of restricted stock	(4,240)	0	(4,240)	0	0	0
Distributions to noncontrolling interest	(11)	0	0	0	0	(11)
BALANCE at Mar. 31, 2021	$ 1,316,798	4	1,652,445	(334,000)	(2,538)	887
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common dividends declared - per share (in dollars per share)	$ 0.79
Issuance of shares of common stock, common stock offering, net of expenses	317,538
Withheld shares of common stock to satisfy tax withholding obligations in connection with vesting of restricted stock shares	30,252
BALANCE at Dec. 31, 2020	$ 1,270,518	4	1,610,053	(329,667)	(10,752)	880
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	85,727
Net unrealized change in fair value of interest rate swaps	8,276
BALANCE at Sep. 30, 2021	1,419,740	4	1,765,748	(344,378)	(2,476)	842
BALANCE at Mar. 31, 2021	1,316,798	4	1,652,445	(334,000)	(2,538)	887
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	27,578	0	0	27,558	0	20
Net unrealized change in fair value of interest rate swaps	(1,263)	0	0	0	(1,263)	0
Common dividends declared	(31,981)	0	0	(31,981)	0	0
Stock-based compensation, net of forfeitures	2,893	0	2,893	0	0	0
Issuance of common stock, common stock offering, net of expenses	59,318	0	59,318	0	0	0
Distributions to noncontrolling interest	(12)	0	5	0	0	(17)
BALANCE at Jun. 30, 2021	$ 1,373,331	4	1,714,661	(338,423)	(3,801)	890
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common dividends declared - per share (in dollars per share)	$ 0.79
Issuance of shares of common stock, common stock offering, net of expenses	370,177
Net Income	$ 30,792	0	0	30,771	0	21
Net unrealized change in fair value of interest rate swaps	1,325	0	0	0	1,325	0
Common dividends declared	(36,726)	0	0	(36,726)	0	0
Stock-based compensation, net of forfeitures	2,461	0	2,461	0	0	0
Issuance of common stock, common stock offering, net of expenses	48,626	0	48,626	0	0	0
Distributions to noncontrolling interest	(69)	0	0	0	0	(69)
BALANCE at Sep. 30, 2021	$ 1,419,740	$ 4	$ 1,765,748	$ (344,378)	$ (2,476)	$ 842
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common dividends declared - per share (in dollars per share)	$ 0.90
Issuance of shares of common stock, common stock offering, net of expenses	278,893