Revenues - Products and Services (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2019	Sep. 30, 2018	Sep. 29, 2019	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Revenues	$ 620,318	$ 655,774	$ 1,845,023	$ 1,929,978
Enterprise Solutions
Disaggregation of Revenue [Line Items]
Revenues	368,080	388,851	1,064,469	1,134,876
Industrial Solutions
Disaggregation of Revenue [Line Items]
Revenues	252,238	266,923	780,554	795,102
Products
Disaggregation of Revenue [Line Items]
Revenues	577,724	611,967	1,719,998	1,804,202
Products | Enterprise Solutions
Disaggregation of Revenue [Line Items]
Revenues	346,501	368,389	1,004,631	1,080,549
Products | Industrial Solutions
Disaggregation of Revenue [Line Items]
Revenues	231,223	243,578	715,367	723,653
Support & Services
Disaggregation of Revenue [Line Items]
Revenues	42,594	43,807	125,025	125,776
Support & Services | Enterprise Solutions
Disaggregation of Revenue [Line Items]
Revenues	21,579	20,462	59,838	54,327
Support & Services | Industrial Solutions
Disaggregation of Revenue [Line Items]
Revenues	$ 21,015	$ 23,345	$ 65,187	$ 71,449