Revenue from Contracts with Customers - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									$ 3,085,177	$ 3,008,652	$ 2,935,586
Net Sales									3,085,177	3,008,652	2,935,586
Revenues	$ 937,985	$ 807,357	$ 690,673	$ 649,162	$ 843,968	$ 753,866	$ 731,366	$ 679,452	3,085,177	3,008,652	2,935,586
Contract with Customer, Asset, after Allowance for Credit Loss	22,600				17,400				22,600	17,400	12,400
Contract with Customer, Liability	$ 149,106				$ 122,489				149,106	122,489	105,381	$ 107,166
Customer prepayments and deferred revenue									617,643	633,190	619,257
Contract with Customer, Liability, Revenue Recognized									(595,802)	(615,957)	(618,002)
Temporary Equity, Foreign Currency Translation Adjustments									4,776	(125)	(3,040)
Americas [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									1,180,626
Net Sales										1,165,847
Europe [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									921,266
Net Sales										892,092
Asia [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									983,285
Net Sales										950,713
Product [Member]
Disaggregation of Revenue [Line Items]
Revenues									2,405,172	2,346,845	2,300,075
Product [Member] | Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									2,405,172	2,346,845	2,300,075
Service [Member]
Disaggregation of Revenue [Line Items]
Revenues									680,005	661,807	635,511
Service [Member] | Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									508,020	511,459	488,962
Service [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									$ 171,985	150,348	146,549
Laboratory products and services [Member]
Disaggregation of Revenue [Line Items]
Percentage of Disaggregated Revenue in Relationship to Segments	54.00%								54.00%
Revenue from Contract with Customer, Excluding Assessed Tax									$ 1,669,791
Revenues										1,578,625	1,504,600
Industrial products and services [Member]
Disaggregation of Revenue [Line Items]
Percentage of Disaggregated Revenue in Relationship to Segments	40.00%								40.00%
Revenue from Contract with Customer, Excluding Assessed Tax									$ 1,224,497
Revenues										1,233,970	1,211,362
Retail products and services [Member]
Disaggregation of Revenue [Line Items]
Percentage of Disaggregated Revenue in Relationship to Segments	6.00%								6.00%
Revenue from Contract with Customer, Excluding Assessed Tax									$ 190,889
Revenues										196,057	219,624
US Operations [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									1,072,319	1,057,115	1,007,797
US Operations [Member] | Product [Member] | Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									815,046	801,181	769,971
US Operations [Member] | Service [Member] | Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									199,247	207,707	196,314
US Operations [Member] | Service [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									58,026	48,227	41,512
Swiss Operations [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									143,923	139,499	134,064
Swiss Operations [Member] | Product [Member] | Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									112,542	110,390	106,400
Swiss Operations [Member] | Service [Member] | Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									22,733	20,968	19,430
Swiss Operations [Member] | Service [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									8,648	8,141	8,234
Western European Operations [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									716,715	700,741	718,788
Western European Operations [Member] | Product [Member] | Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									509,385	500,978	517,855
Western European Operations [Member] | Service [Member] | Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									135,793	135,612	134,052
Western European Operations [Member] | Service [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									71,537	64,151	66,881
Chinese Operations [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									578,610	544,716	525,109
Chinese Operations [Member] | Product [Member] | Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									526,231	495,579	475,025
Chinese Operations [Member] | Service [Member] | Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									39,705	37,370	38,528
Chinese Operations [Member] | Service [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									12,674	11,767	11,556
Other Operations [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									573,610	566,581	549,828
Other Operations [Member] | Product [Member] | Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									441,968	438,717	430,824
Other Operations [Member] | Service [Member] | Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									110,542	109,802	100,638
Other Operations [Member] | Service [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									$ 21,100	$ 18,062	$ 18,366