Debt - Deferred Financing Costs, Net (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Debt Instrument [Line Items]
Financing costs	$ 25,587		$ 24,446
Less: accumulated amortization	(7,364)		(7,039)
Total deferred financing costs, net	18,223		17,407
Amortization of deferred financing costs	1,000	$ 1,300
Unsecured term loan facility | Unsecured Revolving Credit Facility
Debt Instrument [Line Items]
Net deferred financing costs	$ 7,800		$ 8,300