CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (Unaudited) - USD ($) $ in Thousands	Total	5.625% Series C Cumulative Redeemable Preferred Stock	Common Stock	Total Stockholders’ Equity	Total Stockholders’ Equity 5.625% Series C Cumulative Redeemable Preferred Stock	Total Stockholders’ Equity Common Stock	Preferred Stock	Preferred Stock 5.625% Series C Cumulative Redeemable Preferred Stock	Common Stock	Common Stock Common Stock	Additional Paid-in Capital	Additional Paid-in Capital Common Stock	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 stock	515,385	$ 86,250		515,385	$ 86,250			$ 86,250	$ 139		515,246
Issuance of stock (in shares)									13,957,083
Offering costs	(11,276)			(11,276)			(2,963)				(8,313)
Issuance of cumulative redeemable convertible preferred units	27,359														27,359
Share-based compensation	8,080			1,740					$ 1		1,739				6,340
Share-based compensation (in shares)									94,478
Shares acquired to satisfy employee tax withholding requirements on vesting restricted stock	(831)			(831)							(831)
Shares acquired to satisfy employee tax withholding requirements on vesting restricted stock (in shares)									(24,132)
Conversion of OP units to common stock	0			328					$ 0		328				(328)
Conversion of OP units to common stock (in shares)									46,339
Net income	39,619			38,331			7,419						30,912		1,288
Other comprehensive income (loss)	(16,772)			(16,394)										(16,394)	(378)
Dividends, Preferred Stock	(7,271)			(7,271)			(7,271)
Preferred unit distributions	(570)														(570)
Dividends, Common Stock	(60,060)			(60,060)									(60,060)
Distributions	(1,571)														(1,571)
Cumulative effect of adoption of ASC 842	(222)			(222)									(222)
Ending Balance at Sep. 30, 2019	2,486,543			2,422,074			242,529		$ 1,106		2,306,282		(117,711)	(10,132)	64,469
Ending Balance (in shares) at Sep. 30, 2019									110,884,272
Beginning Balance at Jun. 30, 2019	2,364,609			2,301,881			159,094		$ 1,095		2,255,849		(107,056)	(7,101)	62,728
Beginning Balance (in shares) at Jun. 30, 2019									109,739,580
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of stock		$ 86,250	$ 50,726		$ 86,250	$ 50,726		$ 86,250		$ 11		$ 50,715
Issuance of stock (in shares)									1,147,417
Offering costs	(3,837)			(3,837)			(2,963)				(874)
Share-based compensation	2,716			597					$ 0		597				2,119
Share-based compensation (in shares)									(3,736)
Shares acquired to satisfy employee tax withholding requirements on vesting restricted stock	(15)			(15)							(15)
Shares acquired to satisfy employee tax withholding requirements on vesting restricted stock (in shares)									(361)
Conversion of OP units to common stock	0			10							10				(10)
Conversion of OP units to common stock (in shares)									1,372
Net income	12,948			12,430			2,572						9,858		518
Other comprehensive income (loss)	(3,096)			(3,031)										(3,031)	(65)
Dividends, Preferred Stock	(2,424)			(2,424)			(2,424)
Preferred unit distributions	(300)														(300)
Dividends, Common Stock	(20,513)			(20,513)									(20,513)
Distributions	(521)														(521)
Ending Balance at Sep. 30, 2019	2,486,543			2,422,074			242,529		$ 1,106		2,306,282		(117,711)	(10,132)	64,469
Ending Balance (in shares) at Sep. 30, 2019									110,884,272
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 stock	$ 377,336			377,336					$ 96		377,240
Issuance of stock (in shares)									9,643,270
Offering costs	(2,977)			(2,977)							(2,977)
Issuance of OP Units	(67,482)														(67,482)
Issuance of cumulative redeemable convertible preferred units	40,787														40,787
Share-based compensation	10,546			2,375					$ 1		2,374				8,171
Share-based compensation (in shares)									110,595
Shares acquired to satisfy employee tax withholding requirements on vesting restricted stock	(1,254)			(1,254)							(1,254)
Shares acquired to satisfy employee tax withholding requirements on vesting restricted stock (in shares)									(26,961)
Conversion of OP units to common stock	0			6,740					$ 3		6,737				(6,740)
Conversion of OP units to common stock (in shares)									268,387
Net income	62,740			59,408			10,909						48,499		3,332
Other comprehensive income (loss)	(13,147)			(12,689)										(12,689)	(458)
Dividends, Preferred Stock	(10,909)			(10,909)			(10,909)
Preferred unit distributions	(1,838)														(1,838)
Dividends, Common Stock	(78,240)			(78,240)									(78,240)
Distributions	(2,755)														(2,755)
Ending Balance at Sep. 30, 2020	$ 3,070,220			2,895,967			242,327		$ 1,236		2,821,127		(148,492)	(20,231)	174,253
Ending Balance (in shares) at Sep. 30, 2020	123,788,591								123,788,591
Beginning Balance at Jun. 30, 2020	$ 3,065,739			2,893,658			242,327		$ 1,236		2,820,216		(147,907)	(22,214)	172,081
Beginning Balance (in shares) at Jun. 30, 2020									123,789,199
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of stock	0			0					$ 0		0
Issuance of stock (in shares)									0
Offering costs	(23)			(23)							(23)
Issuance of OP Units	0														0
Share-based compensation	3,154			817					$ 0		817				2,337
Share-based compensation (in shares)									(5,187)
Shares acquired to satisfy employee tax withholding requirements on vesting restricted stock	(18)			(18)							(18)
Shares acquired to satisfy employee tax withholding requirements on vesting restricted stock (in shares)									(388)
Conversion of OP units to common stock	0			135					$ 0		135				(135)
Conversion of OP units to common stock (in shares)									4,967
Net income	31,197			29,666			3,636						26,030		1,531
Other comprehensive income (loss)	2,047			1,983										1,983	64
Dividends, Preferred Stock	(3,636)			(3,636)			(3,636)
Preferred unit distributions	(708)														(708)
Dividends, Common Stock	(26,615)			(26,615)									(26,615)
Distributions	(917)														(917)
Ending Balance at Sep. 30, 2020	$ 3,070,220			$ 2,895,967			$ 242,327		$ 1,236		$ 2,821,127		$ (148,492)	$ (20,231)	$ 174,253
Ending Balance (in shares) at Sep. 30, 2020	123,788,591								123,788,591