Commitments and Contingencies - Operating Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Operating Leases, Rent Expense	$ 5,600	$ 5,900	$ 5,800
Future Operating Lease Minimum Payments, Due Next Year	5,279
Future Operating Lease Minimum Payments, Due in Two Years	2,967
Future Operating Lease Minimum Payments, Due in Three Years	2,613
Future Operating Lease Minimum Payments, Due in Four Years	2,225
Future Operating Lease Minimum Payments, Due in Five Years	1,962
Future Operating Lease Minimum Payments, Due Therafter	$ 9,758