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, 2015	$ 262,288	$ 477	$ 410,217	$ (148,406)
Beginning balance (shares) at Dec. 31, 2015		47,664,742
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, net	200,398	$ 170	200,228
Issuance of common stock, net (shares)		17,023,824
Vesting of restricted common stock, net of shares withheld for employee taxes	(515)	$ 1	(516)
Vesting of restricted common stock, net of shares withheld for employee taxes (shares)		127,784
Amortization of stock-based compensation	1,546		1,546
Common dividends ($0.82, $0.74 and $0.68 per share for the years ended 2018, 2017 and 2016, respectively)	(40,640)			(40,640)
Net income	29,353			29,353
Ending balance at Dec. 31, 2016	452,430	$ 648	611,475	(159,693)
Ending balance (shares) at Dec. 31, 2016		64,816,350
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, net	170,319	$ 106	170,213
Issuance of common stock, net (shares)		10,573,089
Vesting of restricted common stock, net of shares withheld for employee taxes	(866)	$ 1	(867)
Vesting of restricted common stock, net of shares withheld for employee taxes (shares)		88,763
Amortization of stock-based compensation	2,416		2,416
Common dividends ($0.82, $0.74 and $0.68 per share for the years ended 2018, 2017 and 2016, respectively)	(55,556)			(55,556)
Net income	25,874			25,874
Ending balance at Dec. 31, 2017	594,617	$ 755	783,237	(189,375)
Ending 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 ($0.82, $0.74 and $0.68 per share for the years ended 2018, 2017 and 2016, 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