Revenue (Disaggregation of revenue) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 624,703	$ 581,268
Operating Segments [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	608,136	557,903
Operating Segments [Member] | Industrial Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	124,560	117,186
Operating Segments [Member] | Aerospace And Defense Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	97,867	99,900
Operating Segments [Member] | Medical Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	97,287	84,925
Operating Segments [Member] | Test And Instrumentation Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	102,214	75,750
Operating Segments [Member] | Computing Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	103,538	100,259
Operating Segments [Member] | Telecommunications Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	82,670	79,883
Elimination Of Intersegment Sales [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	16,567	23,365
Americas [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	378,785	361,320
Americas [Member] | Operating Segments [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	372,119	353,488
Americas [Member] | Operating Segments [Member] | Industrial Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	52,729	54,097
Americas [Member] | Operating Segments [Member] | Aerospace And Defense Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	88,414	93,409
Americas [Member] | Operating Segments [Member] | Medical Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	54,992	47,601
Americas [Member] | Operating Segments [Member] | Test And Instrumentation Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	45,869	32,654
Americas [Member] | Operating Segments [Member] | Computing Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	86,221	77,813
Americas [Member] | Operating Segments [Member] | Telecommunications Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	43,894	47,914
Americas [Member] | Elimination Of Intersegment Sales [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	6,666	7,832
Asia [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	195,122	179,304
Asia [Member] | Operating Segments [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	185,268	163,824
Asia [Member] | Operating Segments [Member] | Industrial Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	53,657	45,791
Asia [Member] | Operating Segments [Member] | Aerospace And Defense Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	1,130	132
Asia [Member] | Operating Segments [Member] | Medical Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	38,263	32,477
Asia [Member] | Operating Segments [Member] | Test And Instrumentation Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	39,233	34,694
Asia [Member] | Operating Segments [Member] | Computing Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	14,900	19,566
Asia [Member] | Operating Segments [Member] | Telecommunications Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	38,085	31,164
Asia [Member] | Elimination Of Intersegment Sales [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	9,854	15,480
Europe [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	50,796	40,644
Europe [Member] | Operating Segments [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	50,749	40,591
Europe [Member] | Operating Segments [Member] | Industrial Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	18,174	17,298
Europe [Member] | Operating Segments [Member] | Aerospace And Defense Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	8,323	6,359
Europe [Member] | Operating Segments [Member] | Medical Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	4,032	4,847
Europe [Member] | Operating Segments [Member] | Test And Instrumentation Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	17,112	8,402
Europe [Member] | Operating Segments [Member] | Computing Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	2,417	2,880
Europe [Member] | Operating Segments [Member] | Telecommunications Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	691	805
Europe [Member] | Elimination Of Intersegment Sales [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 47	$ 53