Consolidated Statements of Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Cumulative Distributions in Excess of Earnings
Beginning balance at Dec. 31, 2017	$ 594,617	$ 755	$ 783,237	$ (189,375)
Beginning balance (shares) at Dec. 31, 2017		75,478,202
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, net	179,886	$ 103	179,783
Issuance of common stock, net (shares)		10,264,981
Vesting of restricted common stock, net of shares withheld for employee taxes	(1,289)	$ 1	(1,290)
Vesting of restricted common stock, net of shares withheld for employee taxes (shares)		123,861
Amortization of stock-based compensation	3,848		3,848
Common dividends ($1.00, $0.90 and $0.82 per share for the years ended 2020, 2019 and 2018, respectively)	(66,738)			(66,738)
Net income	57,923			57,923
Ending balance at Dec. 31, 2018	768,247	$ 859	965,578	(198,190)
Ending balance (shares) at Dec. 31, 2018		85,867,044
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, net	195,924	$ 91	195,833
Issuance of common stock, net (shares)		9,100,250
Vesting of restricted common stock, net of shares withheld for employee taxes	(2,524)	$ 1	(2,525)
Vesting of restricted common stock, net of shares withheld for employee taxes (shares)		135,976
Amortization of stock-based compensation	4,104		4,104
Common dividends ($1.00, $0.90 and $0.82 per share for the years ended 2020, 2019 and 2018, respectively)	(84,519)			(84,519)
Net income	46,359			46,359
Ending balance at Dec. 31, 2019	927,591	$ 951	1,162,990	(236,350)
Ending balance (shares) at Dec. 31, 2019		95,103,270
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, net	(404)	$ 0	(404)
Issuance of common stock, net (shares)		0
Vesting of restricted common stock, net of shares withheld for employee taxes	(1,995)	$ 1	(1,996)
Vesting of restricted common stock, net of shares withheld for employee taxes (shares)		112,527
Amortization of stock-based compensation	3,812		3,812
Common dividends ($1.00, $0.90 and $0.82 per share for the years ended 2020, 2019 and 2018, respectively)	(95,729)			(95,729)
Net income	80,867			80,867
Ending balance at Dec. 31, 2020	$ 914,142	$ 952	$ 1,164,402	$ (251,212)
Ending balance (shares) at Dec. 31, 2020		95,215,797