Segment Information (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Jan. 31, 2017	Oct. 31, 2016	Jul. 31, 2016	Apr. 30, 2016	Jan. 31, 2016	Oct. 31, 2015	Jul. 31, 2015	Apr. 30, 2015	Jan. 31, 2017		Jan. 31, 2016		Jan. 31, 2015
Segment Reporting Information
Net sales to unaffiliated customers:		$ 7,427,510	$ 6,490,265	$ 6,353,739	$ 5,963,362	$ 7,483,621	$ 6,428,540	$ 6,580,393	$ 5,887,229	$ 26,234,876		$ 26,379,783		$ 27,670,632
Stock-based compensation expense										(13,947)		(14,890)		(13,668)
Operating income:		103,117	62,872	73,355	52,558	145,202	68,053	106,235	81,938	291,902		401,428		267,635
Depreciation and amortization:										54,437		57,253		68,746
Capital expenditures:										39,335		33,972		28,175
Identifiable assets:		7,931,866				6,358,288				7,931,866		6,358,288
Long-lived assets:		74,239				66,028				74,239		66,028
Goodwill & acquisition-related intangible assets, net:		279,298				310,016				279,298		310,016
Business Combination, Acquisition Related Costs		14,000	$ 13,000	2,000						28,966		0		0
LCD settlements and other, net				$ (3,700)	$ (400)	(35,400)	$ (3,000)	$ (21,500)	$ (38,500)	(4,142)		(98,433)		(5,059)
Value added tax assessments										1,049		(8,796)		(6,229)
Restatement and remediation related expenses										0		829		22,043
Americas
Segment Reporting Information
Net sales to unaffiliated customers:	[1]									10,384,523		10,356,716		10,406,209
Operating income:										144,246	[2]	235,577	[3]	145,107	[4]
Depreciation and amortization:										$ 18,844		$ 18,243		$ 16,653
Sales to Unaffiliated Customers, as Percentage of Total Sales										90.00%		90.00%		85.00%
Capital expenditures:										$ 19,275		$ 18,139		$ 13,798
Identifiable assets:		3,238,162				2,078,443				3,238,162		2,078,443
Long-lived assets:	[1]	35,581				29,402				35,581		29,402
Goodwill & acquisition-related intangible assets, net:		$ 33,296				$ 35,615				$ 33,296		$ 35,615
Long-lived Assets, as Percentage of Total Assets		94.00%				95.00%				94.00%		95.00%
Business Combination, Acquisition Related Costs										$ 18,000
LCD settlements and other, net										(4,100)		$ (98,433)		(5,100)
Restatement and remediation related expenses														4,000
Europe
Segment Reporting Information
Net sales to unaffiliated customers:										15,850,353		16,023,067		17,264,423
Operating income:										161,603	[5]	180,741	[6]	136,196	[7]
Depreciation and amortization:										35,593		39,010		52,093
Capital expenditures:										20,060		15,833		14,377
Identifiable assets:		$ 4,693,704				$ 4,279,845				4,693,704		4,279,845
Long-lived assets:		38,658				36,626				38,658		36,626
Goodwill & acquisition-related intangible assets, net:		$ 246,002				$ 274,401				246,002		274,401
Europe | Spain
Segment Reporting Information
Business Combination, Acquisition Related Costs										11,000
Value added tax assessments										$ 1,500				(6,229)
Restatement and remediation related expenses														$ 18,100
Europe | Value added tax assessment | European Subsidiary
Segment Reporting Information
Value added tax assessments												$ (8,800)

[1] Net sales to unaffiliated customers in the United States represented 90%, 90% and 85% of the total Americas' net sales to unaffiliated customers for the fiscal years ended January 31, 2017, 2016 and 2015, respectively. Total long-lived assets in the United States represented 94% and 95% of the Americas' total long-lived assets at January 31, 2017 and 2016, respectively.

[2] Operating income in the Americas for the fiscal year ended January 31, 2017 includes acquisition and integration expenses of $18.0 million (see further discussion in Note 5 - Acquisitions) and a gain recorded in LCD settlements and other, net, of $4.1 million (see further discussion in Note 1 – Business and Summary of Significant Accounting Policies).

[3] Operating income in the Americas for the fiscal year ended January 31, 2016 includes a gain recorded in LCD settlements and other, net, of $98.4 million (see further discussion in Note 1 – Business and Summary of Significant Accounting Policies).

[4] Operating income in the Americas for the fiscal year ended January 31, 2015 includes a gain recorded in LCD settlements and other, net, of $5.1 million and restatement and remediation related expenses of $4.0 million (see Note 1 – Business and Summary of Significant Accounting Policies).

[5] Operating income in Europe for the fiscal year ended January 31, 2017 includes acquisition and integration expenses of $11.0 million (see further discussion in Note 5 - Acquisitions) and an increase in the accrual for assessments and penalties for a VAT matter in the Company's subsidiary in Spain of $1.5 million (see further discussion in Note 13 - Commitments and Contingencies).

[6] Operating income in Europe for the fiscal year ended January 31, 2016 includes a net benefit of $8.8 million related to various VAT matters in two European subsidiaries (see further discussion in Note 13 – Commitments and Contingencies).

[7] Operating income in Europe for the fiscal year ended January 31, 2015 includes restatement and remediation related expenses of $18.1 million (see further discussion in Note 1 – Business and Summary of Significant Accounting Policies) and a decrease in the accrual for value added tax matters in the Company's Spanish subsidiary of $6.2 million (see further discussion in Note 13 – Commitments and Contingencies).