Revenue (Disaggregation of revenue) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 575,094	$ 657,344	$ 1,822,751	$ 1,960,308
Operating Segments [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	555,229	640,688	1,759,651	1,909,415
Operating Segments [Member] | Industrials Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	114,973	128,304	346,010	372,048
Operating Segments [Member] | Aerospace And Defense Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	115,354	104,988	326,208	301,284
Operating Segments [Member] | Medical Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	127,773	96,300	345,438	290,103
Operating Segments [Member] | Semi-Cap Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	68,051	76,608	196,522	285,276
Operating Segments [Member] | Computing Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	59,522	145,386	316,522	409,561
Operating Segments [Member] | Telecommunications Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	69,556	89,102	228,951	251,143
Elimination Of Intersegment Sales [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	19,865	16,656	63,100	50,893
Americas [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	344,361	404,137	1,140,581	1,217,200
Americas [Member] | Operating Segments [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	333,785	396,172	1,103,746	1,195,085
Americas [Member] | Operating Segments [Member] | Industrials Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	41,328	45,334	127,714	141,966
Americas [Member] | Operating Segments [Member] | Aerospace And Defense Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	108,101	97,141	302,961	278,191
Americas [Member] | Operating Segments [Member] | Medical Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	79,201	58,725	205,575	173,192
Americas [Member] | Operating Segments [Member] | Semi-Cap Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	23,998	32,016	78,536	125,603
Americas [Member] | Operating Segments [Member] | Computing Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	47,364	125,110	277,538	352,747
Americas [Member] | Operating Segments [Member] | Telecommunications Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	33,793	37,846	111,422	123,386
Americas [Member] | Elimination Of Intersegment Sales [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	10,576	7,965	36,835	22,115
Asia [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	188,092	210,153	549,671	602,903
Asia [Member] | Operating Segments [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	178,985	201,601	523,957	574,398
Asia [Member] | Operating Segments [Member] | Industrials Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	55,454	67,969	162,681	180,195
Asia [Member] | Operating Segments [Member] | Aerospace And Defense Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	0	0	0	0
Asia [Member] | Operating Segments [Member] | Medical Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	44,582	34,404	126,486	106,769
Asia [Member] | Operating Segments [Member] | Semi-Cap Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	31,332	30,494	79,801	111,280
Asia [Member] | Operating Segments [Member] | Computing Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	12,158	18,018	38,899	50,446
Asia [Member] | Operating Segments [Member] | Telecommunications Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	35,459	50,716	116,090	125,708
Asia [Member] | Elimination Of Intersegment Sales [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	9,107	8,552	25,714	28,505
Europe [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	42,641	43,054	132,499	140,205
Europe [Member] | Operating Segments [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	42,459	42,915	131,948	139,932
Europe [Member] | Operating Segments [Member] | Industrials Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	18,191	15,001	55,615	49,887
Europe [Member] | Operating Segments [Member] | Aerospace And Defense Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	7,253	7,847	23,247	23,093
Europe [Member] | Operating Segments [Member] | Medical Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	3,990	3,171	13,377	10,142
Europe [Member] | Operating Segments [Member] | Semi-Cap Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	12,721	14,098	38,185	48,393
Europe [Member] | Operating Segments [Member] | Computing Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	0	2,258	85	6,368
Europe [Member] | Operating Segments [Member] | Telecommunications Sector [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	304	540	1,439	2,049
Europe [Member] | Elimination Of Intersegment Sales [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 182	$ 139	$ 551	$ 273