Segment Information (Details) - USD ($) $ in Thousands		3 Months Ended				9 Months Ended
		Oct. 31, 2017		Oct. 31, 2016		Oct. 31, 2017		Oct. 31, 2016		Jan. 31, 2017
Segment Reporting Information
Net sales:		$ 9,135,728		$ 6,490,265		$ 25,682,482		$ 18,807,366
Operating income:		79,567		62,872		258,176		188,785
Stock-based compensation expense		(8,325)		(3,550)		(21,217)		(11,020)
Depreciation and amortization:		42,334		13,128		112,907		41,223
Capital expenditures:		172,166		8,568		213,979		30,903
Identifiable assets:		10,959,853				10,959,853				$ 7,931,866
Long-lived assets:		273,568				273,568				74,239
Goodwill & acquisition-related intangible assets, net:		1,816,086				1,816,086				279,298
LCD settlements and other, net		0		0		(41,343)		(4,142)
Acquisition, integration and restructuring expenses		29,748		13,015		101,931		14,997
Americas
Segment Reporting Information
Net sales:		3,997,159		2,614,347		11,658,471		7,677,237
Operating income:		55,551	[1]	32,414	[1]	194,426	[2]	104,930	[2]
Depreciation and amortization:		$ 24,645		$ 4,323		$ 62,308		$ 14,118
Sales to unaffiliated customers, as percentage of total sales	[3]	90.00%		91.00%		89.00%		90.00%
Capital expenditures:		$ 167,210		$ 4,004		$ 195,169		$ 15,489
Identifiable assets:		4,776,955				4,776,955				3,238,162
Long-lived assets:		212,141				212,141				35,581
Goodwill & acquisition-related intangible assets, net:		$ 1,131,298				$ 1,131,298				$ 33,296
Long-lived assets, as percentage of total assets		97.00%				97.00%				94.00%
LCD settlements and other, net						$ (42,600)		(4,100)
Acquisition, integration and restructuring expenses		$ 14,100		9,500		58,600		10,500
Europe
Segment Reporting Information
Net sales:		4,841,961		3,875,918		13,250,935		11,130,129
Operating income:	[4]	29,909		34,008		73,172		94,875
Depreciation and amortization:		15,734		8,805		44,957		27,105
Capital expenditures:		4,450		4,564		16,764		15,414
Identifiable assets:		5,721,621				5,721,621				$ 4,693,704
Long-lived assets:		55,528				55,528				38,658
Goodwill & acquisition-related intangible assets, net:		632,793				632,793				246,002
Acquisition, integration and restructuring expenses		14,100		3,500		40,400		4,500
Asia-Pacific
Segment Reporting Information
Net sales:		296,608		0		773,076		0
Operating income:		2,432		0		11,795		0
Depreciation and amortization:		1,955		0		5,642		0
Capital expenditures:		506		$ 0		2,046		$ 0
Identifiable assets:		461,277				461,277				0
Long-lived assets:		5,899				5,899				0
Goodwill & acquisition-related intangible assets, net:		$ 51,995				$ 51,995				$ 0

[1] Operating income in the Americas for the three months ended October 31, 2017 and 2016 includes acquisition, integration and restructuring expenses of $14.1 million and $9.5 million, respectively (see further discussion in Note 3 - Acquisitions)

[2] Operating income in the Americas for the nine months ended October 31, 2017 and 2016 includes acquisition, integration and restructuring expenses of $58.6 million and $10.5 million, respectively and a gain related to LCD settlements and other, net, of $42.6 million and $4.1 million, respectively.

[3] Net sales in the United States represented 90% and 91%, respectively, of the total Americas' net sales for the three months ended October 31, 2017 and 2016, and 89% and 90% respectively, of the total America's net sales for the nine months ended October 31, 2017 and 2016. Total long-lived assets in the United States represented 97% and 94%, respectively, of the Americas' total long-lived assets at October 31, 2017 and January 31, 2017.

[4] Operating income in Europe for the three months ended October 31, 2017 and 2016, includes acquisition, integration and restructuring expenses of $14.1 million and $3.5 million, respectively, and for the nine months ended October 31, 2017 and 2016, includes acquisition, integration and restructuring expenses of $40.4 million and $4.5 million, respectively.