Commitments and Contingencies Contingent Consideration (Acquisitions) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition, Contingent Consideration [Line Items]
Current portion of contingent consideration	$ 6,293	$ 2,826
Contingent consideration non-current portion	18,008	2,349
Bio Helix
Business Acquisition, Contingent Consideration [Line Items]
Contingent consideration—BNP Business	4,600	5,200
Fair Value, Inputs, Level 3 [Member]
Business Acquisition, Contingent Consideration [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings	$ 80	$ 500	$ 100