Segment Information (Details) - USD ($) $ in Thousands		3 Months Ended				6 Months Ended
		Jul. 31, 2017		Jul. 31, 2016		Jul. 31, 2017		Jul. 31, 2016		Jan. 31, 2017
Segment Reporting Information
Net sales:		$ 8,882,691		$ 6,353,739		$ 16,546,754		$ 12,317,101
Operating income:		103,531		73,355		178,609		125,913
Stock-based compensation expense		(7,974)		(3,813)		(12,892)		(7,470)
Depreciation and amortization:		38,890		14,048		70,573		28,095
Capital expenditures:		11,367		10,772		41,813		22,335
Identifiable assets:		11,373,925				11,373,925				$ 7,931,866
Long-lived assets:		136,577				136,577				74,239
Goodwill & acquisition-related intangible assets, net:		1,856,691				1,856,691				279,298
LCD settlements and other, net		(28,655)		(3,699)		(41,343)		(4,142)
Acquisition, integration and restructuring expenses		30,117		1,982		72,183		1,982
Americas
Segment Reporting Information
Net sales:	[1]	4,192,475		2,674,886		7,661,312		5,062,890
Operating income:		87,975	[2]	41,241	[2]	138,875	[3]	72,516	[3]
Depreciation and amortization:		$ 20,971		$ 4,905		$ 37,663		$ 9,795
Sales to unaffiliated customers, as percentage of total sales		88.00%		91.00%		87.00%		89.00%
Capital expenditures:		$ 7,087		$ 5,388		$ 27,959		$ 11,485
Identifiable assets:		5,053,728				5,053,728				3,238,162
Long-lived assets:	[1]	73,493				73,493				35,581
Goodwill & acquisition-related intangible assets, net:		$ 1,152,428				$ 1,152,428				$ 33,296
Long-lived assets, as percentage of total assets		95.00%				95.00%				94.00%
LCD settlements and other, net		$ (30,000)		(3,700)		$ (42,600)		(4,100)
Acquisition, integration and restructuring expenses		14,300		1,100		44,400		1,100
Europe
Segment Reporting Information
Net sales:		4,402,054		3,678,853		8,408,974		7,254,211
Operating income:	[4]	18,464		35,927		43,263		60,867
Depreciation and amortization:		15,690		9,143		29,223		18,300
Capital expenditures:		2,920		5,384		12,314		10,850
Identifiable assets:		5,812,357				5,812,357				$ 4,693,704
Long-lived assets:		56,914				56,914				38,658
Goodwill & acquisition-related intangible assets, net:		649,764				649,764				246,002
Acquisition, integration and restructuring expenses		14,700		900		26,200		900
Asia-Pacific
Segment Reporting Information
Net sales:		288,162		0		476,468		0
Operating income:		5,066		0		9,363		0
Depreciation and amortization:		2,229		0		3,687		0
Capital expenditures:		1,360		$ 0		1,540		$ 0
Identifiable assets:		507,840				507,840				0
Long-lived assets:		6,170				6,170				0
Goodwill & acquisition-related intangible assets, net:		$ 54,499				$ 54,499				$ 0

[1] Net sales in the United States represented 88% and 91%, respectively, of the total Americas' net sales for the three months ended July 31, 2017 and 2016, and 87% and 89% respectively, of the total America's net sales for the six months ended July 31, 2017 and 2016. Total long-lived assets in the United States represented 95% and 94%, respectively, of the Americas' total long-lived assets at July 31, 2017 and January 31, 2017.

[2] Operating income in the Americas for the three months ended July 31, 2017 and 2016 includes acquisition, integration and restructuring expenses of $14.3 million and $1.1 million, respectively (see further discussion in Note 3 - Acquisitions) and a gain related to LCD settlements and other, net, of $30.0 million and $3.7 million, respectively (see further discussion in Note 1 – Business and Summary of Significant Accounting Policies).

[3] Operating income in the Americas for the six months ended July 31, 2017 and 2016 includes acquisition, integration and restructuring expenses of $44.4 million and $1.1 million, respectively and a gain related to LCD settlements and other, net, of $42.6 million and $4.1 million, respectively.

[4] Operating income in Europe for the three months ended July 31, 2017 and 2016, includes acquisition, integration and restructuring expenses of $14.7 million and $0.9 million, respectively, and for the six months ended July 31, 2017 and 2016, includes acquisition, integration and restructuring expenses of $26.2 million and $0.9 million, respectively.