Segment Information (Details) - USD ($) $ in Thousands		3 Months Ended				9 Months Ended
		Oct. 31, 2016		Oct. 31, 2015		Oct. 31, 2016		Oct. 31, 2015		Jan. 31, 2016
Segment Reporting Information
Net sales to unaffiliated customers:		$ 6,490,265		$ 6,428,540		$ 18,807,366		$ 18,896,162
Operating income:		62,872		68,053		188,785		256,226
Stock-based compensation expense		(3,550)		(3,621)		(11,020)		(11,399)
Depreciation and amortization:		13,128		14,347		41,223		42,518
Capital expenditures:		8,568		8,181		30,903		23,177
Identifiable assets:		6,462,664				6,462,664				$ 6,358,288
Long-lived assets:		72,700				72,700				66,028
Goodwill & acquisition-related intangible assets, net:		283,851				283,851				310,016
Acquisition and integration expenses		13,015		0		14,997		0
Gain (Loss) Related to Litigation Settlement		0		3,049		4,142		63,087
Value added tax assessments		0		0		1,049		(9,563)
Americas
Segment Reporting Information
Net sales to unaffiliated customers:	[1]	2,614,347		2,572,751		7,677,237		7,657,440
Operating income:		32,414	[2]	38,857	[3]	104,930	[2],[3]	161,968	[3]
Depreciation and amortization:		$ 4,323		$ 4,884		$ 14,118		$ 13,397
Sales to unaffiliated customers, as percentage of total sales		91.00%		91.00%		90.00%		90.00%
Capital expenditures:		$ 4,004		$ 4,046		$ 15,489		$ 12,132
Identifiable assets:		2,302,283				2,302,283				2,078,443
Long-lived assets:	[1]	34,805				34,805				29,402
Goodwill & acquisition-related intangible assets, net:		$ 33,874				$ 33,874				$ 35,615
Long-lived assets, as percentage of total assets		95.00%				95.00%				95.00%
Acquisition and integration expenses		$ 9,500				$ 10,500
Gain (Loss) Related to Litigation Settlement				3,049		4,142		63,087
Europe
Segment Reporting Information
Net sales to unaffiliated customers:		3,875,918		3,855,789		11,130,129		11,238,722
Operating income:	[4]	34,008		32,817		94,875		105,657
Depreciation and amortization:		8,805		9,463		27,105		29,121
Capital expenditures:		4,564		$ 4,135		15,414		11,045
Identifiable assets:		4,160,381				4,160,381				$ 4,279,845
Long-lived assets:		37,895				37,895				36,626
Goodwill & acquisition-related intangible assets, net:		249,977				249,977				$ 274,401
Acquisition and integration expenses		$ 3,500				4,500
Value added tax assessments						$ 1,500		$ (9,563)

[1] Net sales to unaffiliated customers in the United States represented 91% of the total Americas' net sales to unaffiliated customers for the three months ended October 31, 2016 and 2015, and 90% of the total Americas' net sales to unaffiliated customers for the nine months ended October 31, 2016 and 2015. Total long-lived assets in the United States represented 95% of the Americas' total long-lived assets at October 31, 2016 and January 31, 2016.

[2] Operating income in the Americas includes acquisition and integration expenses of $9.5 million and $10.5 million, respectively, for the three and nine months ended October 31, 2016. Operating income in Europe includes acquisition and integration expenses of $3.5 million and $4.5 million, respectively, for the three and nine months ended October 31, 2016 (see further discussion in Note 3 – Acquisitions).

[3] Operating income in the Americas includes a gain recorded in LCD settlements and other, net, of $4.1 million for the nine months ended October 31, 2016, and $3.0 million and $63.1 million, respectively, for the three and nine months ended October 31, 2015 (see further discussion in Note 1 – Business and Summary of Significant Accounting Policies).

[4] Operating income in Europe for the nine months ended October 31, 2016 includes an increase of $1.5 million in the accrual for assessments and penalties for a VAT matter in the Company's subsidiary in Spain. Operating income in Europe for the three and nine months ended October 31, 2015 includes a net decrease of $9.6 million in the accrual for assessments and penalties for various VAT matters in two European subsidiaries (see further discussion in Note 9 – Commitments & Contingencies).