Summarized Condensed Consolidating Information - Condensed Consolidating Balance Sheets (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017
Assets:
Real estate investments, net	$ 1,404,024			$ 1,216,237
Other real estate investments, net	44,808			18,045
Assets held for sale, net	34,590			0
Cash and cash equivalents	5,749			36,792
Accounts and other receivables, net	2,125			11,387
Prepaid expenses and other assets	30,202			8,668
Deferred financing costs, net	3,268			633
Investment in subsidiaries	0			0
Intercompany	0			0
Total assets	1,524,766			1,291,762
Liabilities and Equity:
Senior unsecured notes payable, net	295,721			295,153
Senior unsecured term loan, net	198,661			99,612
Unsecured revolving credit facility	65,000			95,000
Accounts payable and accrued liabilities	16,251			15,967
Dividends payable	21,647			17,783
Intercompany	0			0
Total liabilities	597,280			523,515
Equity:
Common stock, $0.01 par value; 500,000,000 shares authorized, 95,103,270 and 85,867,044 shares issued and outstanding as of September 30, 2019 and December 31, 2018, respectively	951			859
Additional paid-in capital	1,162,047			965,578
Cumulative distributions in excess of earnings	(235,512)			(198,190)
Total equity	927,486	$ 958,137	$ 811,031	768,247	$ 720,050	$ 638,738	$ 593,888	$ 594,617
Total liabilities and equity	1,524,766			1,291,762
Reportable Legal Entities | Parent Guarantor
Assets:
Real estate investments, net	0			0
Other real estate investments, net	0			0
Assets held for sale, net	0
Cash and cash equivalents	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	949,133			786,030
Intercompany	0			0
Total assets	949,133			786,030
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	21,647			17,783
Intercompany	0			0
Total liabilities	21,647			17,783
Equity:
Common stock, $0.01 par value; 500,000,000 shares authorized, 95,103,270 and 85,867,044 shares issued and outstanding as of September 30, 2019 and December 31, 2018, respectively	951			859
Additional paid-in capital	1,162,047			965,578
Cumulative distributions in excess of earnings	(235,512)			(198,190)
Total equity	927,486			768,247
Total liabilities and equity	949,133			786,030
Reportable Legal Entities | Issuers
Assets:
Real estate investments, net	878,848			887,921
Other real estate investments, net	41,728			12,299
Assets held for sale, net	34,590
Cash and cash equivalents	5,749			36,792
Accounts and other receivables, net	2,104			9,359
Prepaid expenses and other assets	30,198			8,666
Deferred financing costs, net	3,268			633
Investment in subsidiaries	524,410			484,955
Intercompany	3,108			0
Total assets	1,524,003			1,440,625
Liabilities and Equity:
Senior unsecured notes payable, net	295,721			295,153
Senior unsecured term loan, net	198,661			99,612
Unsecured revolving credit facility	65,000			95,000
Accounts payable and accrued liabilities	15,488			13,588
Dividends payable	0			0
Intercompany	0			151,242
Total liabilities	574,870			654,595
Equity:
Common stock, $0.01 par value; 500,000,000 shares authorized, 95,103,270 and 85,867,044 shares issued and outstanding as of September 30, 2019 and December 31, 2018, respectively	0			0
Additional paid-in capital	795,857			661,686
Cumulative distributions in excess of earnings	153,276			124,344
Total equity	949,133			786,030
Total liabilities and equity	1,524,003			1,440,625
Reportable Legal Entities | Combined Subsidiary Guarantors
Assets:
Real estate investments, net	525,176			328,316
Other real estate investments, net	3,080			5,746
Assets held for sale, net	0
Cash and cash equivalents	0			0
Accounts and other receivables, net	21			2,028
Prepaid expenses and other assets	4			2
Deferred financing costs, net	0			0
Investment in subsidiaries	0			0
Intercompany	0			151,242
Total assets	528,281			487,334
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	763			2,379
Dividends payable	0			0
Intercompany	3,108			0
Total liabilities	3,871			2,379
Equity:
Common stock, $0.01 par value; 500,000,000 shares authorized, 95,103,270 and 85,867,044 shares issued and outstanding as of September 30, 2019 and December 31, 2018, respectively	0			0
Additional paid-in capital	321,761			321,761
Cumulative distributions in excess of earnings	202,649			163,194
Total equity	524,410			484,955
Total liabilities and equity	528,281			487,334
Elimination
Assets:
Real estate investments, net	0			0
Other real estate investments, net	0			0
Assets held for sale, net	0
Cash and cash equivalents	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	(1,473,543)			(1,270,985)
Intercompany	(3,108)			(151,242)
Total assets	(1,476,651)			(1,422,227)
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	(3,108)			(151,242)
Total liabilities	(3,108)			(151,242)
Equity:
Common stock, $0.01 par value; 500,000,000 shares authorized, 95,103,270 and 85,867,044 shares issued and outstanding as of September 30, 2019 and December 31, 2018, respectively	0			0
Additional paid-in capital	(1,117,618)			(983,447)
Cumulative distributions in excess of earnings	(355,925)			(287,538)
Total equity	(1,473,543)			(1,270,985)
Total liabilities and equity	$ (1,476,651)			$ (1,422,227)