Acquisitions Business Combinations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Sep. 01, 2017
Business Acquisition [Line Items]
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability	$ (18,674)	$ 0	$ 0
Goodwill, Acquired During Period	558	52,229
Amortization of Intangible Assets	14,300	11,500	8,300
BIOTIX [Member]
Business Acquisition [Line Items]
Business Combination, Consideration Transferred		105,000
Business Combination, Contingent Consideration, Liability				$ 30,700
Payment for Contingent Consideration Liability, Financing Activities	10,000
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability	18,700
Goodwill, Acquired During Period		51,700
Amortization of Intangible Assets		3,700
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net		$ 18,800
Minimum Weighted Average Useful Lives		5 years
Maximum Weighted Average Useful Lives		18 years
Other Acquisitions [Member]
Business Acquisition [Line Items]
Business Combination, Consideration Transferred	5,500	$ 3,800	111,400
Goodwill, Acquired During Period	600	300
Finite-lived Intangible Assets Acquired	$ 4,900	$ 3,100
Maximum Weighted Average Useful Lives	10 years	12
Henry Troemner, LLC [Member]
Business Acquisition [Line Items]
Business Combination, Consideration Transferred			95,800
Goodwill, Acquired During Period			41,300
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net			$ 60,100
Minimum Weighted Average Useful Lives			3 years
Maximum Weighted Average Useful Lives			25 years
Customer Relationships [Member] | BIOTIX [Member]
Business Acquisition [Line Items]
Finite-lived Intangible Assets Acquired		$ 49,500
Technology-Based Intangible Assets [Member] | BIOTIX [Member]
Business Acquisition [Line Items]
Finite-lived Intangible Assets Acquired		8,000
Other Intangible Assets [Member] | BIOTIX [Member]
Business Acquisition [Line Items]
Finite-lived Intangible Assets Acquired		600
Trade Names [Member] | BIOTIX [Member]
Business Acquisition [Line Items]
Finite-lived Intangible Assets Acquired		$ 7,100