Acquisitions Fauchier Acquisition (Details) £ in Thousands, $ in Thousands		3 Months Ended
		Mar. 31, 2013 USD ($)	Mar. 31, 2016 GBP (£)	Mar. 31, 2016 USD ($)		May. 05, 2015 GBP (£)	May. 05, 2015 USD ($)
Business Acquisition [Line Items]
Business Acquisition, Preacquisition Contingency, Amount of Settlement				$ 22,765
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High	[1]			609,608
Fauchier [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross		$ 63,433
Business Acquisition, Preacquisition Contingency, Amount of Settlement						£ (15,000)	$ (22,765)
Fauchier [Member] | Contingent Payment due on fourth anniversary of acquisition
Business Acquisition [Line Items]
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High			£ 20,000	$ 28,743	[1]

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