Debt - Schedule of Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Principal Amount	$ 565,000	$ 495,000
Deferred Loan Fees(1)	(5,618)	(5,235)
Carrying Value	559,382	489,765
Senior unsecured notes payable
Debt Instrument [Line Items]
Principal Amount	300,000	300,000
Deferred Loan Fees(1)	(4,279)	(4,847)
Carrying Value	295,721	295,153
Senior unsecured term loan
Debt Instrument [Line Items]
Principal Amount	200,000	100,000
Deferred Loan Fees(1)	(1,339)	(388)
Carrying Value	198,661	99,612
Unsecured revolving credit facility
Debt Instrument [Line Items]
Principal Amount	65,000	95,000
Deferred Loan Fees(1)	0	0
Carrying Value	$ 65,000	$ 95,000