Summarized Condensed Consolidating Information - Condensed Consolidating Statements of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash flows from operating activities:
Net cash provided by operating activities	$ 30,074	$ 22,059
Cash flows from investing activities:
Acquisitions of real estate	(52,697)	(47,103)
Improvements to real estate	(452)	(11)
Purchases of equipment, furniture and fixtures	(1,806)	(27)
Investment in real estate mortgage and other loans receivable	(11,389)	0
Principal payments received on real estate mortgage and other loans receivable	411	23
Escrow deposits for acquisitions of real estate	(375)	(1,000)
Net proceeds from the sale of real estate	131	13,004
Distribution from subsidiary	0	0
Intercompany financing	0	0
Net cash used in investing activities	(66,177)	(35,114)
Cash flows from financing activities:
Proceeds from the issuance of common stock, net	47,260	(10)
Proceeds from the issuance of senior unsecured term loan	200,000	0
Borrowings under unsecured revolving credit facility	185,000	60,000
Payments on senior unsecured term loan	(100,000)	0
Payments on unsecured revolving credit facility	(95,000)	(25,000)
Payments of deferred financing costs	(4,390)	0
Net-settle adjustment on restricted stock	(1,495)	(605)
Dividends paid on common stock	(17,710)	(14,044)
Distribution to Parent	0	0
Intercompany financing	0	0
Net cash provided by financing activities	213,665	20,341
Net increase in cash and cash equivalents	177,562	7,286
Cash and cash equivalents, beginning of period	36,792	6,909
Cash and cash equivalents, end of period	214,354	14,195
Reportable Legal Entities | Parent Guarantor
Cash flows from operating activities:
Net cash provided by operating activities	0	0
Cash flows from investing activities:
Acquisitions of real estate	0	0
Improvements to real estate	0	0
Purchases of equipment, furniture and fixtures	0	0
Investment in real estate mortgage and other loans receivable	0
Principal payments received on real estate mortgage and other loans receivable	0	0
Escrow deposits for acquisitions of real estate	0	0
Net proceeds from the sale of real estate	0	0
Distribution from subsidiary	17,710	14,044
Intercompany financing	(45,765)	615
Net cash used in investing activities	(28,055)	14,659
Cash flows from financing activities:
Proceeds from the issuance of common stock, net	47,260	(10)
Proceeds from the issuance of senior unsecured term loan	0
Borrowings under unsecured revolving credit facility	0	0
Payments on senior unsecured term loan	0
Payments on unsecured revolving credit facility	0	0
Payments of deferred financing costs	0
Net-settle adjustment on restricted stock	(1,495)	(605)
Dividends paid on common stock	(17,710)	(14,044)
Distribution to Parent	0	0
Intercompany financing	0	0
Net cash provided by financing activities	28,055	(14,659)
Net increase in cash and cash equivalents	0	0
Cash and cash equivalents, beginning of period	0	0
Cash and cash equivalents, end of period	0	0
Reportable Legal Entities | Issuers
Cash flows from operating activities:
Net cash provided by operating activities	15,308	7,295
Cash flows from investing activities:
Acquisitions of real estate	(52,697)	(47,103)
Improvements to real estate	(452)	0
Purchases of equipment, furniture and fixtures	(1,806)	(23)
Investment in real estate mortgage and other loans receivable	(11,389)
Principal payments received on real estate mortgage and other loans receivable	411	23
Escrow deposits for acquisitions of real estate	(375)	(1,000)
Net proceeds from the sale of real estate	131	13,004
Distribution from subsidiary	0	0
Intercompany financing	14,766	14,749
Net cash used in investing activities	(51,411)	(20,350)
Cash flows from financing activities:
Proceeds from the issuance of common stock, net	0	0
Proceeds from the issuance of senior unsecured term loan	200,000
Borrowings under unsecured revolving credit facility	185,000	60,000
Payments on senior unsecured term loan	(100,000)
Payments on unsecured revolving credit facility	(95,000)	(25,000)
Payments of deferred financing costs	(4,390)
Net-settle adjustment on restricted stock	0	0
Dividends paid on common stock	0	0
Distribution to Parent	(17,710)	(14,044)
Intercompany financing	45,765	(615)
Net cash provided by financing activities	213,665	20,341
Net increase in cash and cash equivalents	177,562	7,286
Cash and cash equivalents, beginning of period	36,792	6,909
Cash and cash equivalents, end of period	214,354	14,195
Reportable Legal Entities | Combined Subsidiary Guarantors
Cash flows from operating activities:
Net cash provided by operating activities	14,766	14,764
Cash flows from investing activities:
Acquisitions of real estate	0	0
Improvements to real estate	0	(11)
Purchases of equipment, furniture and fixtures	0	(4)
Investment in real estate mortgage and other loans receivable	0
Principal payments received on real estate mortgage and other loans receivable	0	0
Escrow deposits for acquisitions of real estate	0	0
Net proceeds from the sale of real estate	0	0
Distribution from subsidiary	0	0
Intercompany financing	0	0
Net cash used in investing activities	0	(15)
Cash flows from financing activities:
Proceeds from the issuance of common stock, net	0	0
Proceeds from the issuance of senior unsecured term loan	0
Borrowings under unsecured revolving credit facility	0	0
Payments on senior unsecured term loan	0
Payments on unsecured revolving credit facility	0	0
Payments of deferred financing costs	0
Net-settle adjustment on restricted stock	0	0
Dividends paid on common stock	0	0
Distribution to Parent	0	0
Intercompany financing	(14,766)	(14,749)
Net cash provided by financing activities	(14,766)	(14,749)
Net increase in cash and cash equivalents	0	0
Cash and cash equivalents, beginning of period	0	0
Cash and cash equivalents, end of period	0	0
Elimination
Cash flows from operating activities:
Net cash provided by operating activities	0	0
Cash flows from investing activities:
Acquisitions of real estate	0	0
Improvements to real estate	0	0
Purchases of equipment, furniture and fixtures	0	0
Investment in real estate mortgage and other loans receivable	0
Principal payments received on real estate mortgage and other loans receivable	0	0
Escrow deposits for acquisitions of real estate	0	0
Net proceeds from the sale of real estate	0	0
Distribution from subsidiary	(17,710)	(14,044)
Intercompany financing	30,999	(15,364)
Net cash used in investing activities	13,289	(29,408)
Cash flows from financing activities:
Proceeds from the issuance of common stock, net	0	0
Proceeds from the issuance of senior unsecured term loan	0
Borrowings under unsecured revolving credit facility	0	0
Payments on senior unsecured term loan	0
Payments on unsecured revolving credit facility	0	0
Payments of deferred financing costs	0
Net-settle adjustment on restricted stock	0	0
Dividends paid on common stock	0	0
Distribution to Parent	17,710	14,044
Intercompany financing	(30,999)	15,364
Net cash provided by financing activities	(13,289)	29,408
Net increase in cash and cash equivalents	0	0
Cash and cash equivalents, beginning of period	0	0
Cash and cash equivalents, end of period	$ 0	$ 0