Commitments and Contingencies - Concentration Risk (Details) - amendment	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Customer A | Customer Concentration Risk | Revenues
Concentration Risk [Line Items]
Concentration risk	19.60%
Customer B | Accounts Receivable | Customer Receivable
Concentration Risk [Line Items]
Concentration risk		12.90%
Customer B | Customer Concentration Risk | Revenues
Concentration Risk [Line Items]
Concentration risk	14.50%	15.60%
Customer C | Customer Concentration Risk | Revenues
Concentration Risk [Line Items]
Concentration risk	12.70%	11.20%
Customer D
Concentration Risk [Line Items]
Number of contract amendments		2
Ownership interest, noncontrolling interest		2.20%
Customer D | Accounts Receivable | Customer Receivable
Concentration Risk [Line Items]
Concentration risk		23.20%
Customer D | Customer Concentration Risk | Revenues
Concentration Risk [Line Items]
Concentration risk		19.60%
Customer E | Customer Concentration Risk | Revenues
Concentration Risk [Line Items]
Concentration risk		14.10%
Customer F | Accounts Receivable | Customer Receivable
Concentration Risk [Line Items]
Concentration risk		28.10%
Customer F | Customer Concentration Risk | Revenues
Concentration Risk [Line Items]
Concentration risk		11.80%
Customer G | Accounts Receivable | Customer Receivable
Concentration Risk [Line Items]
Concentration risk		11.40%
Customer H | Accounts Receivable | Customer Receivable
Concentration Risk [Line Items]
Concentration risk	14.30%