CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (Unaudited) - USD ($) $ in Thousands	Total	Total Stockholders’ Equity	Preferred Stock	Common Stock	Additional Paid-in Capital	Cumulative Distributions in Excess of Earnings	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interests
Beginning Balance at Dec. 31, 2018	$ 1,908,423	$ 1,876,094	$ 159,094	$ 966	$ 1,798,113	$ (88,341)	$ 6,262	$ 32,329
Beginning Balance (in shares) at Dec. 31, 2018				96,810,504
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock (in shares)				12,809,666
Issuance of common stock	464,659	464,659		$ 128	464,531
Offering costs	(7,439)	(7,439)			(7,439)
Share-based compensation (in shares)				98,214
Share-based compensation	5,364	1,143		$ 1	1,142			4,221
Shares acquired to satisfy employee tax withholding requirements on vesting restricted stock (in shares)				(23,771)
Shares acquired to satisfy employee tax withholding requirements on vesting restricted stock	(816)	(816)			(816)
Conversion of units to common stock (in shares)				44,967
Conversion of units to common stock	0	318		$ 0	318			(318)
Net income	26,671	25,901	4,847			21,054		770
Other comprehensive income (loss)	(13,676)	(13,363)					(13,363)	(313)
Preferred stock dividends	(4,847)	(4,847)	(4,847)
Preferred unit distributions	(270)							(270)
Common stock dividends	(39,547)	(39,547)				(39,547)
Distributions	(1,050)							(1,050)
Issuance of cumulative redeemable convertible preferred units	27,359							27,359
Cumulative effect of adoption of ASC 842	(222)	(222)				(222)
Ending Balance at Jun. 30, 2019	2,364,609	2,301,881	159,094	$ 1,095	2,255,849	(107,056)	(7,101)	62,728
Ending Balance (in shares) at Jun. 30, 2019				109,739,580
Beginning Balance at Mar. 31, 2019	2,137,836	2,103,896	159,094	$ 1,038	2,042,218	(99,715)	1,261	33,940
Beginning Balance (in shares) at Mar. 31, 2019				104,028,046
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock (in shares)				5,660,920
Issuance of common stock	216,265	216,265		$ 57	216,208
Offering costs	(3,465)	(3,465)			(3,465)
Share-based compensation (in shares)				11,295
Share-based compensation	2,751	632		$ 0	632			2,119
Shares acquired to satisfy employee tax withholding requirements on vesting restricted stock (in shares)				(681)
Shares acquired to satisfy employee tax withholding requirements on vesting restricted stock	(25)	(25)			(25)
Conversion of units to common stock (in shares)				40,000
Conversion of units to common stock	0	281			281			(281)
Net income	15,954	15,385	2,424			12,961		569
Other comprehensive income (loss)	(8,549)	(8,362)					(8,362)	(187)
Preferred stock dividends	(2,424)	(2,424)	(2,424)
Preferred unit distributions	(270)							(270)
Common stock dividends	(20,302)	(20,302)				(20,302)
Distributions	(521)							(521)
Issuance of cumulative redeemable convertible preferred units	27,359							27,359
Ending Balance at Jun. 30, 2019	2,364,609	2,301,881	159,094	$ 1,095	2,255,849	(107,056)	(7,101)	62,728
Ending Balance (in shares) at Jun. 30, 2019				109,739,580
Beginning Balance at Dec. 31, 2019	$ 2,622,449	2,556,177	242,327	$ 1,136	2,439,007	(118,751)	(7,542)	66,272
Beginning Balance (in shares) at Dec. 31, 2019	113,793,300			113,793,300
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock (in shares)				9,643,270
Issuance of common stock	$ 377,336	377,336		$ 96	377,240
Offering costs	(2,954)	(2,954)			(2,954)
Issuance of OP Units	(67,482)							(67,482)
Share-based compensation (in shares)				115,782
Share-based compensation	7,392	1,558		$ 1	1,557			5,834
Shares acquired to satisfy employee tax withholding requirements on vesting restricted stock (in shares)				(26,573)
Shares acquired to satisfy employee tax withholding requirements on vesting restricted stock	(1,236)	(1,236)			(1,236)
Conversion of units to common stock (in shares)				263,420
Conversion of units to common stock	0	6,605		$ 3	6,602			(6,605)
Net income	31,543	29,742	7,273			22,469		1,801
Other comprehensive income (loss)	(15,194)	(14,672)					(14,672)	(522)
Preferred stock dividends	(7,273)	(7,273)	(7,273)
Preferred unit distributions	(1,130)							(1,130)
Common stock dividends	(51,625)	(51,625)				(51,625)
Distributions	(1,838)							(1,838)
Issuance of cumulative redeemable convertible preferred units	40,787							40,787
Ending Balance at Jun. 30, 2020	$ 3,065,739	2,893,658	242,327	$ 1,236	2,820,216	(147,907)	(22,214)	172,081
Ending Balance (in shares) at Jun. 30, 2020	123,789,199			123,789,199
Beginning Balance at Mar. 31, 2020	$ 2,778,678	2,612,970	242,327	$ 1,162	2,524,274	(132,843)	(21,950)	165,708
Beginning Balance (in shares) at Mar. 31, 2020				116,331,347
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock (in shares)				7,436,313
Issuance of common stock	296,522	296,522		$ 74	296,448
Offering costs	(1,571)	(1,571)			(1,571)
Issuance of OP Units	(4,205)							(4,205)
Share-based compensation (in shares)				13,507
Share-based compensation	3,765	859		$ 0	859			2,906
Shares acquired to satisfy employee tax withholding requirements on vesting restricted stock (in shares)				(776)
Shares acquired to satisfy employee tax withholding requirements on vesting restricted stock	(29)	(29)			(29)
Conversion of units to common stock (in shares)				8,808
Conversion of units to common stock	0	235		$ 0	235			(235)
Net income	16,271	15,187	3,637			11,550		1,084
Other comprehensive income (loss)	(226)	(264)					(264)	38
Preferred stock dividends	(3,637)	(3,637)	(3,637)
Preferred unit distributions	(707)							(707)
Common stock dividends	(26,614)	(26,614)				(26,614)
Distributions	(918)							(918)
Ending Balance at Jun. 30, 2020	$ 3,065,739	$ 2,893,658	$ 242,327	$ 1,236	$ 2,820,216	$ (147,907)	$ (22,214)	$ 172,081
Ending Balance (in shares) at Jun. 30, 2020	123,789,199			123,789,199