Debt - Schedule of Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Oct. 22, 2015
Debt Instrument [Line Items]
Total Debt	$ 474,728	$ 460,428
Unamortized deferred financing costs	(3,160)	(3,956)
Total debt	471,568	456,472
Line of Credit | Key Bank Credit Facility
Debt Instrument [Line Items]
Total Debt	$ 347,758	333,458
Contractual interest rate	2.74%
Effective interest rate (percent)	2.96%
Notes Payable, Other Payables | AIG Loan
Debt Instrument [Line Items]
Total Debt	$ 126,970	$ 126,970
Total debt			$ 127,000
Contractual interest rate	4.15%
Effective interest rate (percent)	4.22%