Interim Financial Information (Unaudited) (Condensed Income Statement)(Details) - USD ($) $ / shares in Units, $ 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
Condensed Financial Statements, Captions
Net sales	$ 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
Gross profit	371,027	315,839	316,450	298,611	354,649	314,844	325,279	291,889	1,301,927		1,286,661		1,393,954
Operating income	103,117	62,872	73,355	52,558	145,202	68,053	106,235	81,938	291,902		401,428		267,635
Net income	78,822	36,506	46,394	33,373	96,147	41,900	76,412	51,277	195,095		265,736		175,172
Gain (Loss) Related to Litigation Settlement			3,700	$ 400	$ 35,400	$ 3,000	$ 21,500	$ 38,500	4,142		98,433		5,059
Business Combination, Acquisition Related Costs	$ 14,000	$ 13,000	$ 2,000						28,966		0		0
Value added tax assessments									$ 1,049		$ (8,796)		$ (6,229)
Earnings per share:
Basic	$ 2.24	$ 1.04	$ 1.32	$ 0.95	$ 2.74	$ 1.19	$ 2.09	$ 1.39	$ 5.54		$ 7.40		$ 4.59
Diluted	$ 2.22	$ 1.03	$ 1.31	$ 0.94	$ 2.72	$ 1.18	$ 2.09	$ 1.38	$ 5.51		$ 7.36		$ 4.57
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount									$ (13,400)		$ (11,300)
European Subsidiary | Value added tax assessment
Condensed Financial Statements, Captions
Value added tax assessments					$ 800		$ (9,600)				7,600
Europe
Condensed Financial Statements, Captions
Net sales									15,850,353		16,023,067		$ 17,264,423
Operating income									161,603	[1]	$ 180,741	[2]	136,196	[3]
Earnings per share:
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount									$ (12,500)				$ (19,200)

[1] 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).

[2] 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).

[3] 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).