Segment Information - Accounts Receivable (Details)	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2016
Customer D [Domain] | Accounts Receivable [Member]
Concentration Risk [Line Items]
Entity-Wide Revenue, Major Customer, Percentage	21.50%		18.70%
Customer C [Domain]
Concentration Risk [Line Items]
Entity-Wide Revenue, Major Customer, Percentage	12.50%
Customer C [Domain] | Accounts Receivable [Member]
Concentration Risk [Line Items]
Entity-Wide Revenue, Major Customer, Percentage	15.10%
Customer B [Domain]
Concentration Risk [Line Items]
Entity-Wide Revenue, Major Customer, Percentage	40.70%	15.00%
Customer B [Domain] | Accounts Receivable [Member]
Concentration Risk [Line Items]
Entity-Wide Revenue, Major Customer, Percentage	33.40%		19.10%
Customer A [Domain]
Concentration Risk [Line Items]
Entity-Wide Revenue, Major Customer, Percentage		41.20%