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, 2014	$ 113,462	$ 313	$ 246,041	$ (132,892)
Beginning balance (shares) at Dec. 31, 2014		31,251,157
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, net	162,963	$ 163	162,800
Issuance of common stock, net (shares)		16,330,000
Vesting of restricted common stock, net of shares withheld for employee taxes	(145)	$ 1	(146)
Vesting of restricted common stock, net of shares withheld for employee taxes (shares)		83,585
Amortization of stock-based compensation	1,522		1,522
Common dividends ($0.74, $0.68 and $0.64 per share for the years ended 2017, 2016 and 2015, respectively)	(25,548)			(25,548)
Net income	10,034			10,034
Ending balance at Dec. 31, 2015	262,288	$ 477	410,217	(148,406)
Ending 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 ($0.74, $0.68 and $0.64 per share for the years ended 2017, 2016 and 2015, 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 ($0.74, $0.68 and $0.64 per share for the years ended 2017, 2016 and 2015, 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