Summarized Condensed Consolidating Information - Condensed Consolidating Balance Sheets (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017
Assets:
Real estate investments, net	$ 1,482,040		$ 1,216,237
Other real estate investments, net	26,725		18,045
Cash and cash equivalents	2,629		36,792
Accounts and other receivables, net	9,705		11,387
Prepaid expenses and other assets	6,947		8,668
Deferred financing costs, net	3,513		633
Investment in subsidiaries	0		0
Intercompany	0		0
Total assets	1,531,559		1,291,762
Liabilities and Equity:
Senior unsecured notes payable, net	295,532		295,153
Senior unsecured term loan, net	198,608		99,612
Unsecured revolving credit facility	45,000		95,000
Accounts payable and accrued liabilities	12,665		15,967
Dividends payable	21,617		17,783
Intercompany	0		0
Total liabilities	573,422		523,515
Equity:
Common stock, $0.01 par value; 500,000,000 shares authorized, 95,073,223 and 85,867,044 shares issued and outstanding as of June 30, 2019 and December 31, 2018, respectively	951		859
Additional paid-in capital	1,161,144		965,578
Cumulative distributions in excess of earnings	(203,958)		(198,190)
Total equity	958,137	$ 811,031	768,247	$ 638,738	$ 593,888	$ 594,617
Total liabilities and equity	1,531,559		1,291,762
Reportable Legal Entities | Parent Guarantor
Assets:
Real estate investments, net	0		0
Other real estate investments, net	0		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	979,754		786,030
Intercompany	0		0
Total assets	979,754		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	21,617		17,783
Intercompany	0		0
Total liabilities	21,617		17,783
Equity:
Common stock, $0.01 par value; 500,000,000 shares authorized, 95,073,223 and 85,867,044 shares issued and outstanding as of June 30, 2019 and December 31, 2018, respectively	951		859
Additional paid-in capital	1,161,144		965,578
Cumulative distributions in excess of earnings	(203,958)		(198,190)
Total equity	958,137		768,247
Total liabilities and equity	979,754		786,030
Reportable Legal Entities | Issuers
Assets:
Real estate investments, net	951,636		887,921
Other real estate investments, net	23,646		12,299
Cash and cash equivalents	2,629		36,792
Accounts and other receivables, net	9,691		9,359
Prepaid expenses and other assets	6,942		8,666
Deferred financing costs, net	3,513		633
Investment in subsidiaries	510,129		484,955
Intercompany	22,720		0
Total assets	1,530,906		1,440,625
Liabilities and Equity:
Senior unsecured notes payable, net	295,532		295,153
Senior unsecured term loan, net	198,608		99,612
Unsecured revolving credit facility	45,000		95,000
Accounts payable and accrued liabilities	12,012		13,588
Dividends payable	0		0
Intercompany	0		151,242
Total liabilities	551,152		654,595
Equity:
Common stock, $0.01 par value; 500,000,000 shares authorized, 95,073,223 and 85,867,044 shares issued and outstanding as of June 30, 2019 and December 31, 2018, respectively	0		0
Additional paid-in capital	817,519		661,686
Cumulative distributions in excess of earnings	162,235		124,344
Total equity	979,754		786,030
Total liabilities and equity	1,530,906		1,440,625
Reportable Legal Entities | Combined Subsidiary Guarantors
Assets:
Real estate investments, net	530,404		328,316
Other real estate investments, net	3,079		5,746
Cash and cash equivalents	0		0
Accounts and other receivables, net	14		2,028
Prepaid expenses and other assets	5		2
Deferred financing costs, net	0		0
Investment in subsidiaries	0		0
Intercompany	0		151,242
Total assets	533,502		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	653		2,379
Dividends payable	0		0
Intercompany	22,720		0
Total liabilities	23,373		2,379
Equity:
Common stock, $0.01 par value; 500,000,000 shares authorized, 95,073,223 and 85,867,044 shares issued and outstanding as of June 30, 2019 and December 31, 2018, respectively	0		0
Additional paid-in capital	321,761		321,761
Cumulative distributions in excess of earnings	188,368		163,194
Total equity	510,129		484,955
Total liabilities and equity	533,502		487,334
Elimination
Assets:
Real estate investments, net	0		0
Other real estate investments, net	0		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	(1,489,883)		(1,270,985)
Intercompany	(22,720)		(151,242)
Total assets	(1,512,603)		(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	(22,720)		(151,242)
Total liabilities	(22,720)		(151,242)
Equity:
Common stock, $0.01 par value; 500,000,000 shares authorized, 95,073,223 and 85,867,044 shares issued and outstanding as of June 30, 2019 and December 31, 2018, respectively	0		0
Additional paid-in capital	(1,139,280)		(983,447)
Cumulative distributions in excess of earnings	(350,603)		(287,538)
Total equity	(1,489,883)		(1,270,985)
Total liabilities and equity	$ (1,512,603)		$ (1,422,227)