Acquisitions Fauchier Acquisition (Details) £ in Thousands, $ in Thousands		3 Months Ended
		Mar. 31, 2013 USD ($)	Dec. 31, 2016 GBP (£)	Dec. 31, 2016 USD ($)	Aug. 31, 2016 USD ($)	Mar. 31, 2016 USD ($)	May 05, 2015 USD ($)
Business Acquisition [Line Items]
Business Acquisition, Preacquisition Contingency, Amount of Settlement				$ 6,587		$ 22,765
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High	[1]			530,399
Fauchier [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross		$ 63,433
Business Acquisition, Preacquisition Contingency, Amount of Settlement					$ (6,587)		$ (22,765)
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High	[1]			$ 24,641
Fauchier [Member] | Contingent payment due on fourth anniversary of acquisition [Member]
Business Acquisition [Line Items]
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High | £			£ 20,000

[1] Using the applicable exchange rate as of December 31, 2016, for amounts denominated in currencies other than the U.S. dollar.