Summarized Condensed Consolidating Information - Condensed Consolidating Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Assets:
Real estate investments, net	$ 1,152,261	$ 893,918
Other real estate investments	17,949	13,872
Cash and cash equivalents	6,909	7,500	$ 11,467	$ 25,320
Accounts and other receivables, net	5,254	5,896
Prepaid expenses and other assets	895	1,369
Deferred financing costs, net	1,718	2,803
Investment in subsidiaries	0	0
Intercompany	0	0
Total assets	1,184,986	925,358
Liabilities and Equity:
Senior unsecured notes payable, net	294,395	255,294
Senior unsecured term loan, net	99,517	99,422
Unsecured revolving credit facility	165,000	95,000
Accounts payable and accrued liabilities	17,413	12,137
Dividends payable	14,044	11,075
Intercompany	0	0
Total liabilities	590,369	472,928
Equity:
Common stock, $0.01 par value; 500,000,000 shares authorized, 75,478,202 and 64,816,350 shares issued and outstanding as of December 31, 2017 and December 31, 2016, respectively	755	648
Additional paid-in capital	783,237	611,475
Cumulative distributions in excess of earnings	(189,375)	(159,693)
Total equity	594,617	452,430	262,288	113,462
Total liabilities and equity	1,184,986	925,358
Reportable Legal Entities | Parent Guarantor
Assets:
Real estate investments, net	0	0
Other real estate investments	0	0
Cash and cash equivalents	0	0	0	0
Accounts and other receivables, net	0	0
Prepaid expenses and other assets	0	0
Deferred financing costs, net	0	0
Investment in subsidiaries	619,075	463,505
Intercompany	0	0
Total assets	619,075	463,505
Liabilities and Equity:
Senior unsecured notes payable, net	0	0
Senior unsecured term loan, net	0	0
Unsecured revolving credit facility	0	0
Accounts payable and accrued liabilities	0	0
Dividends payable	14,044	11,075
Intercompany	0	0
Total liabilities	14,044	11,075
Equity:
Common stock, $0.01 par value; 500,000,000 shares authorized, 75,478,202 and 64,816,350 shares issued and outstanding as of December 31, 2017 and December 31, 2016, respectively	755	648
Additional paid-in capital	783,237	611,475
Cumulative distributions in excess of earnings	(178,961)	(159,693)
Total equity	605,031	452,430
Total liabilities and equity	619,075	463,505
Reportable Legal Entities | Issuers
Assets:
Real estate investments, net	805,826	527,639
Other real estate investments	12,399	0
Cash and cash equivalents	6,909	7,500	11,467	25,320
Accounts and other receivables, net	2,945	3,743
Prepaid expenses and other assets	893	1,366
Deferred financing costs, net	1,718	2,803
Investment in subsidiaries	444,120	401,328
Intercompany	0	0
Total assets	1,274,810	944,379
Liabilities and Equity:
Senior unsecured notes payable, net	294,395	255,294
Senior unsecured term loan, net	99,517	99,422
Unsecured revolving credit facility	165,000	95,000
Accounts payable and accrued liabilities	15,176	9,713
Dividends payable	0	0
Intercompany	92,061	21,445
Total liabilities	666,149	480,874
Equity:
Common stock, $0.01 par value; 500,000,000 shares authorized, 75,478,202 and 64,816,350 shares issued and outstanding as of December 31, 2017 and December 31, 2016, respectively	0	0
Additional paid-in capital	546,097	429,453
Cumulative distributions in excess of earnings	62,564	34,052
Total equity	608,661	463,505
Total liabilities and equity	1,274,810	944,379
Reportable Legal Entities | Combined Subsidiary Guarantors
Assets:
Real estate investments, net	346,435	366,279
Other real estate investments	5,550	13,872
Cash and cash equivalents	0	0	0	0
Accounts and other receivables, net	2,309	2,153
Prepaid expenses and other assets	2	3
Deferred financing costs, net	0	0
Investment in subsidiaries	0	0
Intercompany	92,061	102,273
Total assets	446,357	484,580
Liabilities and Equity:
Senior unsecured notes payable, net	0	0
Senior unsecured term loan, net	0	0
Unsecured revolving credit facility	0	0
Accounts payable and accrued liabilities	2,237	2,424
Dividends payable	0	0
Intercompany	0	80,828
Total liabilities	2,237	83,252
Equity:
Common stock, $0.01 par value; 500,000,000 shares authorized, 75,478,202 and 64,816,350 shares issued and outstanding as of December 31, 2017 and December 31, 2016, respectively	0	0
Additional paid-in capital	321,761	321,761
Cumulative distributions in excess of earnings	122,359	79,567
Total equity	444,120	401,328
Total liabilities and equity	446,357	484,580
Elimination
Assets:
Real estate investments, net	0	0
Other real estate investments	0	0
Cash and cash equivalents	0	0	$ 0	$ 0
Accounts and other receivables, net	0	0
Prepaid expenses and other assets	0	0
Deferred financing costs, net	0	0
Investment in subsidiaries	(1,063,195)	(864,833)
Intercompany	(92,061)	(102,273)
Total assets	(1,155,256)	(967,106)
Liabilities and Equity:
Senior unsecured notes payable, net	0	0
Senior unsecured term loan, net	0	0
Unsecured revolving credit facility	0	0
Accounts payable and accrued liabilities	0	0
Dividends payable	0	0
Intercompany	(92,061)	(102,273)
Total liabilities	(92,061)	(102,273)
Equity:
Common stock, $0.01 par value; 500,000,000 shares authorized, 75,478,202 and 64,816,350 shares issued and outstanding as of December 31, 2017 and December 31, 2016, respectively	0	0
Additional paid-in capital	(867,858)	(751,214)
Cumulative distributions in excess of earnings	(195,337)	(113,619)
Total equity	(1,063,195)	(864,833)
Total liabilities and equity	$ (1,155,256)	$ (967,106)