Consolidated Statements of Equity - USD ($) $ in Thousands	Total	Preferred Stock	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Cumulative Net Income	Cumulative Dividends
Beginning Balance at Dec. 31, 2018	$ 1,716,642	$ 0	$ 1,253	$ 3,180,284	$ (902)	$ 1,088,119	$ (2,552,112)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of stock, net of costs	295,856		92	295,764
Common stock redemption	(3,318)		(1)	(3,317)
Share-based compensation	12,275		3	12,272
Net income	39,185					39,185
Loss on interest rate swaps and treasury locks	(5,273)				(5,273)
Dividends to common stockholders ($1.21 per share)	(155,358)						(155,358)
Ending Balance at Dec. 31, 2019	1,900,009	0	1,347	3,485,003	(6,175)	1,127,304	(2,707,470)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of stock, net of costs	142,170		47	142,123
Common stock redemption	(1,706)		(1)	(1,705)
Share-based compensation	9,922		2	9,920
Net income	72,195					72,195
Gains (losses) arising during the period on interest rate swaps	(11,657)				(11,657)
Dividends to common stockholders ($1.21 per share)	(162,557)						(162,557)
Ending Balance at Dec. 31, 2020	1,948,376	0	1,395	3,635,341	(17,832)	1,199,499	(2,870,027)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of stock, net of costs	331,042		109	330,933
Common stock redemption	(4,085)		(1)	(4,084)
Share-based compensation	10,729		2	10,727
Net income	66,659					66,659
Gains (losses) arising during the period on interest rate swaps	7,851				7,851
Dividends to common stockholders ($1.21 per share)	(175,456)						(175,456)
Ending Balance at Dec. 31, 2021	$ 2,185,116	$ 0	$ 1,505	$ 3,972,917	$ (9,981)	$ 1,266,158	$ (3,045,483)