Commitments and Contingencies - Rental Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Future Cash Payments, Operating Leases:
2017	$ 4,350
2018	3,352
2019	2,450
2020	2,074
2021	1,769
Thereafter	2,110
Total	16,105
Future Cash Payments, Purchase Obligations:
2017	7,042
Total	7,042
Operating leases, rent expense	$ 3,467	$ 3,518	$ 3,320