Segment Reporting Revenues by Division (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Sales Information
Revenue from Contract with Customer, Excluding Assessed Tax									$ 3,008,652	$ 2,935,586
Revenues	$ 843,968	$ 753,866	$ 731,366	$ 679,452	$ 817,923	$ 734,846	$ 721,996	$ 660,821	3,008,652	2,935,586	$ 2,725,053
Laboratory products and services [Member]
Segment Sales Information
Revenue from Contract with Customer, Excluding Assessed Tax									1,578,625
Revenues										1,504,600	1,358,493
Industrial products and services [Member]
Segment Sales Information
Revenue from Contract with Customer, Excluding Assessed Tax									1,233,970
Revenues										1,211,362	1,158,335
Retail products and services [Member]
Segment Sales Information
Revenue from Contract with Customer, Excluding Assessed Tax									$ 196,057
Revenues										$ 219,624	$ 208,225