Segment and Geographic Information - Geographic Sales & PP&E (Details) - USD ($) $ in Thousands		3 Months Ended							12 Months Ended
		Mar. 31, 2018		Dec. 31, 2017	Sep. 30, 2017	Jul. 01, 2017	Apr. 01, 2017		Dec. 31, 2017
Revenues From External Customers And Long Lived Assets [Line Items]
Sales		$ 6,875,613	[1]	$ 7,539,449	$ 6,856,108	$ 6,422,226	$ 5,736,780	[1]	$ 26,554,563
Property, plant, and equipment, net		849,867		838,475					838,475
Americas [Member]
Revenues From External Customers And Long Lived Assets [Line Items]
Property, plant, and equipment, net	[2]	694,312		688,637					688,637
EMEA [Member]
Revenues From External Customers And Long Lived Assets [Line Items]
Property, plant, and equipment, net		112,028		108,232					108,232
Asia Pacific [Member]
Revenues From External Customers And Long Lived Assets [Line Items]
Property, plant, and equipment, net		43,527		41,606					41,606
United States [Member]
Revenues From External Customers And Long Lived Assets [Line Items]
Sales		2,649,668					2,342,128
Property, plant, and equipment, net		689,953		$ 683,988					$ 683,988
Global ECS [Member]
Revenues From External Customers And Long Lived Assets [Line Items]
Sales		1,945,681					1,677,977
Global ECS [Member] | Americas [Member]
Revenues From External Customers And Long Lived Assets [Line Items]
Sales		1,195,411					1,094,643
Global ECS [Member] | EMEA [Member]
Revenues From External Customers And Long Lived Assets [Line Items]
Sales	[3]	750,270					583,334
Global Components [Member]
Revenues From External Customers And Long Lived Assets [Line Items]
Sales		4,929,932					4,058,803
Global Components [Member] | Americas [Member]
Revenues From External Customers And Long Lived Assets [Line Items]
Sales		1,796,698					1,563,545
Global Components [Member] | EMEA [Member]
Revenues From External Customers And Long Lived Assets [Line Items]
Sales	[3]	1,478,386					1,118,279
Global Components [Member] | Asia Pacific [Member]
Revenues From External Customers And Long Lived Assets [Line Items]
Sales		$ 1,654,848					$ 1,376,979

[1] Includes sales related to the United States of $2,649,668 and $2,342,128 for the first quarter of 2018 and 2017, respectively.

[2] Includes net property, plant, and equipment related to the United States of $689,953 and $683,988 at March 31, 2018 and December 31, 2017, respectively.

[3] Defined as Europe, the Middle East, and Africa.