Revenue (Disaggregation of revenue) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 2,566,465	$ 2,454,479	$ 2,322,285
Industrial Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	493,063	496,436	543,803
Aerospace And Defense Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	406,402	391,690	369,674
Medical Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	393,967	373,785	345,974
Test And Instrumentation Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	354,978	346,341	243,407
Computing Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	580,845	540,360	447,182
Telecommunications Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	337,210	305,867	372,245
Operating Segments [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	2,635,231	2,539,299	2,401,658
Elimination Of Intersegment Sales [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	68,766	84,820	79,373
Americas [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	1,617,530	1,554,250	1,565,989
Americas [Member] | Industrial Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	184,500	213,699	307,261
Americas [Member] | Aerospace And Defense Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	374,852	361,200	333,383
Americas [Member] | Medical Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	235,287	204,677	190,167
Americas [Member] | Test And Instrumentation Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	155,687	158,151	125,680
Americas [Member] | Computing Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	504,391	444,401	369,719
Americas [Member] | Telecommunications Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	162,813	172,122	239,779
Americas [Member] | Operating Segments [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	1,647,402	1,584,729	1,589,933
Americas [Member] | Elimination Of Intersegment Sales [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	29,872	30,479	23,944
Asia [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	762,769	723,493	600,159
Asia [Member] | Industrial Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	241,765	213,504	176,184
Asia [Member] | Aerospace And Defense Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	0	2,430	1,113
Asia [Member] | Medical Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	144,528	149,650	136,398
Asia [Member] | Test And Instrumentation Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	135,299	140,967	90,708
Asia [Member] | Computing Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	69,657	85,988	66,695
Asia [Member] | Telecommunications Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	171,520	130,954	129,061
Asia [Member] | Operating Segments [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	801,312	777,616	653,888
Asia [Member] | Elimination Of Intersegment Sales [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	38,543	54,123	53,729
Europe [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	186,166	176,736	156,137
Europe [Member] | Industrial Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	66,798	69,233	60,358
Europe [Member] | Aerospace And Defense Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	31,550	28,060	35,178
Europe [Member] | Medical Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	14,152	19,458	19,409
Europe [Member] | Test And Instrumentation Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	63,992	47,223	27,019
Europe [Member] | Computing Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	6,797	9,971	10,768
Europe [Member] | Telecommunications Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	2,877	2,791	3,405
Europe [Member] | Operating Segments [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	186,517	176,954	157,837
Europe [Member] | Elimination Of Intersegment Sales [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 351	$ 218	$ 1,700