Debt - Line of Credit with FGI (Details) - Line of credit with FGI - Line of Credit - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Sep. 07, 2017
Line of Credit Facility [Line Items]
Maximum borrowing capacity		$ 7.5
Line of credit facility interest rate determinant threshold percentage	6.50%
Interest rate on advances or borrowings	6.50%
Prime Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate	2.50%