Condensed 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 (in shares) at Dec. 31, 2017		75,478,202
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, net	(27)		(27)
Vesting of restricted common stock, net of shares withheld for employee taxes	(605)		(605)
Vesting of restricted common stock, net of shares withheld for employee taxes (in shares)		43,844
Amortization of stock-based compensation	904		904
Common dividends	(15,608)			(15,608)
Net (loss) income	14,607			14,607
Ending balance at Mar. 31, 2018	593,888	$ 755	783,509	(190,376)
Ending balance (in shares) at Mar. 31, 2018		75,522,046
Beginning balance at Dec. 31, 2017	594,617	$ 755	783,237	(189,375)
Beginning balance (in shares) at Dec. 31, 2017		75,478,202
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	42,384
Ending balance at Sep. 30, 2018	720,050	$ 834	915,235	(196,019)
Ending balance (in shares) at Sep. 30, 2018		83,353,226
Beginning balance at Mar. 31, 2018	593,888	$ 755	783,509	(190,376)
Beginning balance (in shares) at Mar. 31, 2018		75,522,046
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, net	47,567	$ 30	47,537
Issuance of common stock, net, (in shares)		2,988,813
Vesting of restricted common stock, net of shares withheld for employee taxes	(684)		(684)
Vesting of restricted common stock, net of shares withheld for employee taxes (in shares)		39,828
Amortization of stock-based compensation	924		924
Common dividends	(16,224)			(16,224)
Net (loss) income	13,267			13,267
Ending balance at Jun. 30, 2018	638,738	$ 785	831,286	(193,333)
Ending balance (in shares) at Jun. 30, 2018		78,550,687
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, net	83,010	$ 48	82,962
Issuance of common stock, net, (in shares)		4,771,910
Vesting of restricted common stock, net of shares withheld for employee taxes	0	$ 1	(1)
Vesting of restricted common stock, net of shares withheld for employee taxes (in shares)		30,629
Amortization of stock-based compensation	988		988
Common dividends	(17,196)			(17,196)
Net (loss) income	14,510			14,510
Ending balance at Sep. 30, 2018	720,050	$ 834	915,235	(196,019)
Ending balance (in shares) at Sep. 30, 2018		83,353,226
Beginning balance at Dec. 31, 2018	768,247	$ 859	965,578	(198,190)
Beginning balance (in shares) at Dec. 31, 2018		85,867,044
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, net	47,243	$ 24	47,219
Issuance of common stock, net, (in shares)		2,459,000
Vesting of restricted common stock, net of shares withheld for employee taxes	(1,495)	$ 1	(1,496)
Vesting of restricted common stock, net of shares withheld for employee taxes (in shares)		72,229
Amortization of stock-based compensation	994		994
Common dividends	(20,011)			(20,011)
Net (loss) income	16,053			16,053
Ending balance at Mar. 31, 2019	811,031	$ 884	1,012,295	(202,148)
Ending balance (in shares) at Mar. 31, 2019		88,398,273
Beginning balance at Dec. 31, 2018	768,247	$ 859	965,578	(198,190)
Beginning balance (in shares) at Dec. 31, 2018		85,867,044
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	25,697
Ending balance at Sep. 30, 2019	927,486	$ 951	1,162,047	(235,512)
Ending balance (in shares) at Sep. 30, 2019		95,103,270
Beginning balance at Mar. 31, 2019	811,031	$ 884	1,012,295	(202,148)
Beginning balance (in shares) at Mar. 31, 2019		88,398,273
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, net	148,798	$ 67	148,731
Issuance of common stock, net, (in shares)		6,641,250
Vesting of restricted common stock, net of shares withheld for employee taxes	(1,029)		(1,029)
Vesting of restricted common stock, net of shares withheld for employee taxes (in shares)		33,700
Amortization of stock-based compensation	1,147		1,147
Common dividends	(21,508)			(21,508)
Net (loss) income	19,698			19,698
Ending balance at Jun. 30, 2019	958,137	$ 951	1,161,144	(203,958)
Ending balance (in shares) at Jun. 30, 2019		95,073,223
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, net	(78)		(78)
Vesting of restricted common stock, net of shares withheld for employee taxes	0
Vesting of restricted common stock, net of shares withheld for employee taxes (in shares)		30,047
Amortization of stock-based compensation	981		981
Common dividends	(21,500)			(21,500)
Net (loss) income	(10,054)			(10,054)
Ending balance at Sep. 30, 2019	$ 927,486	$ 951	$ 1,162,047	$ (235,512)
Ending balance (in shares) at Sep. 30, 2019		95,103,270