4. Intangible Assets, Goodwill and Other (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2020	Dec. 31, 2019
Goodwill [Line Items]
Goodwill	$ 626,700	$ 626,700	$ 599,300
Accumulated impairment loss	(335,200)	(335,200)	(335,200)
Goodwill, net	291,504	291,504	264,131
Goodwill, Acquired During Period	29,400	29,400
Goodwill, Other Increase (Decrease)		2,000
Life Science [Member]
Goodwill [Line Items]
Goodwill	277,500	277,500	250,100
Accumulated impairment loss	(41,800)	(41,800)	(41,800)
Goodwill, net	235,700	235,700	208,300
Goodwill, Acquired During Period	29,400	29,400
Goodwill, Other Increase (Decrease)	2,000	2,000
Clinical Diagnostics [Member]
Goodwill [Line Items]
Goodwill	349,200	349,200	349,200
Accumulated impairment loss	(293,400)	(293,400)	(293,400)
Goodwill, net	$ 55,800	55,800	$ 55,800
Goodwill, Acquired During Period		0
Goodwill, Other Increase (Decrease)		$ 0