Acquisitions and Investments (Details) $ in Thousands		3 Months Ended			12 Months Ended
	Oct. 07, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2017 USD ($) business	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Dec. 31, 2016 USD ($)
Business Acquisition [Line Items]
Goodwill		$ 214,489			$ 239,724	$ 214,489	$ 199,873		$ 178,228
Investment acquired, non-controlling interest share		$ 5,000
Acquisition of a business, net of cash acquired					50,304	22,500	14,579
Payment of acquisition-related contingent consideration					2,375	1,266	$ 0
Reference laboratory in Mid-West, U.S.
Business Acquisition [Line Items]
Purchase price of acquired assets	$ 50,000
Net tangible liabilities	200
Goodwill	24,800
Software company
Business Acquisition [Line Items]
Purchase price of acquired assets			$ 25,000
Net tangible liabilities			300
Goodwill			20,300
Two software companies
Business Acquisition [Line Items]
Purchase price of acquired assets				$ 15,000
Goodwill								$ 13,300
Number of businesses acquired | business				2
Acquisition of a business, net of cash acquired				$ 12,000
Contingent consideration				$ 3,000
Contingent payment period				36 months
Payment of acquisition-related contingent consideration					$ 1,000	$ 1,000
Customer relationships | Reference laboratory in Mid-West, U.S.
Business Acquisition [Line Items]
Intangible assets	$ 25,000
Intangible assets useful life	10 years
Customer relationships | Software company
Business Acquisition [Line Items]
Intangible assets			2,400
Customer relationships | Two software companies
Business Acquisition [Line Items]
Intangible assets								1,000
Technology-based intangible assets | Software company
Business Acquisition [Line Items]
Intangible assets			$ 2,600
Technology-based intangible assets | Two software companies
Business Acquisition [Line Items]
Intangible assets								$ 600