Summary of Significant Accounting Policies (Details Textual)	3 Months Ended		12 Months Ended						1 Months Ended	12 Months Ended					3 Months Ended						1 Months Ended	12 Months Ended						12 Months Ended
	Apr. 30, 2010	Jan. 31, 2010	Jul. 31, 2011 USD ($) Year	Jul. 31, 2010 USD ($)	Jul. 31, 2009 USD ($)	Sep. 10, 2011	Jul. 31, 2008 USD ($)	Jul. 31, 2010 Variable Rate Demand Obligation [Member] USD ($)	Sep. 30, 2011 Class A nonvoting common stock [Member]	Jul. 31, 2011 Class A nonvoting common stock [Member] USD ($)	Jul. 31, 2010 Class A nonvoting common stock [Member] USD ($)	Jul. 31, 2009 Class A nonvoting common stock [Member] USD ($)	Jul. 31, 2011 Common Class A [Member]	Oct. 31, 2011 Common Class A [Member]	Oct. 31, 2009 Welco [Member] USD ($)	Jan. 31, 2010 Stickolor [Member] USD ($)	Apr. 30, 2010 Securimed [Member] USD ($)	Jan. 31, 2011 ID Warehouse [Member] USD ($)	Jan. 31, 2011 Teklynx [Member] USD ($)	Jul. 31, 2011 Frank M. Jaehnert	Aug. 31, 2010 Frank M. Jaehnert Performance Based Restricted Shares [Member]	Jul. 31, 2011 Frank M. Jaehnert Performance Based Restricted Shares [Member]	Jul. 31, 2011 Thomas J. Felmer	Jul. 31, 2011 Peter C. Sephton	Jul. 31, 2011 Matthew O. Williamson	Jul. 31, 2011 Robert L.Tatterson	Jul. 31, 2010 Robert L.Tatterson	Jul. 31, 2011 Performance Based Options [Member]	Jul. 31, 2010 Performance Based Options [Member]	Jul. 31, 2011 Stock Based Options [Member]	Jul. 31, 2010 Stock Based Options [Member]	Jul. 31, 2009 Stock Based Options [Member]	Jul. 31, 2011 Service Based Option [Member]	Jul. 31, 2011 Performance Based Restricted Shares [Member] USD ($)	Jul. 31, 2008 Performance Based Restricted Shares [Member]	Jul. 31, 2011 Foreign Corporate Debt Securities [Member] EUR (€)
Investment Holdings [Line Items]
Cash and cash equivalents			$ 389,971,000	$ 314,840,000	$ 188,156,000		$ 258,355,000	$ 66,100,000
Class of Stock [Line Items]
Dividends									0.74	$ 0.72	$ 0.70	$ 0.68
Dividend Payable														0.185
Percentage Increase in dividends paid													2.80%
Outstanding stock options and restricted shares of Class A Nonvoting Common Stock										5,799,017
Future issuance of stock option and restricted shares										737,000
Business Acquisition [Line Items]
Increase in goodwill			4,792,000	20,266,000											778,000	13,370,000	6,118,000	4,792,000
Increase in goodwill attributed to allocation of purchase price			4,792,000	20,266,000
Current year divestitures			12,076,000																12,076,000
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercisable Performance Based Stock Options			3,316,815	3,100,955	2,831,311															50,000			35,000	35,000	35,000	20,000	20,000
Performance Based Stock Options Granted																					100,000	100,000						465,000					900,500		210,000
Weighted-average exercise price																												28.35	29.78	29.13	28.68	21.26	29.13	$ 28.35
Weighted-average fair value of options granted																												9.87	8.70	9.59	8.77	6.30	9.59	$ 28.35
Performance based restricted share outstanding																																		310,000
Options Outstanding, Granted			1,365,500	1,446,500	614,000
Stock based compensation, net of tax																																		1,200,000
Derivative [Line Items]
Foreign denominated debt outstanding																																				75,000,000
Summary of Significant Accounting Policies (Textuals) [Abstract]
Number of shares authorized for repurchase						2,000,000
Allowances for doubtful accounts			6,183,000	7,137,000
Percentage of maximum customer's shares in company's consolidated net sales			10.00%	10.00%	10.00%
Percentage of maximum customer's shares in company's consolidated accounts receivable			10.00%	10.00%
Percentage of LIFO inventory			16.00%	20.00%
Increase in carrying value of inventory due to change in accounting method			9,168,000	9,178,000
Estimated useful lives range, minimum			3
Estimated useful lives range, maximum			33
Depreciation expense of leasehold improvements			28,997,000	31,560,000	32,023,000
Increase in goodwill due to acquisition and net effects of foreign currency translation			31,743,000	17,427,000
Decrease in goodwill due to net effect of foreign currency translation			(39,027,000)	2,839,000
Amortization of Intangible Assets			19,830,000	21,462,000	22,828,000
Projected Future amortization expense, year one			16,883,000
Projected Future amortization expense, year two			11,029,000
Projected Future amortization expense, year three			5,946,000
Projected Future amortization expense, year four			5,540,000
Projected Future amortization expense, year five			4,353,000
Prepaid catalog costs included in prepaid expenses and other current assets			11,892,000	11,496,000
Sales reserve			4,491,000	3,963,000
Advertising expense			79,326,000	72,000,000	77,395,000
Share-based Compensation			9,830,000	9,721,000	7,731,000
Stock based compensation, net of tax			5,996,000	5,930,000	4,716,000
Unrealized compensation cost related to share-based compensation, pre tax			18,551,000
Weighted Average Period Net of Forfeitures			2.2
No of Years Extended Performance Based Stock Options	10 years	5 years
Foreign Currency Contracts, Liability, Fair Value Disclosure			6,109,000	673,000
Notional amount of outstanding foreign exchange contracts			80,800,000
Unrealized losses on hedged transactions			1,535,000	493,000
Net Investment hedges of the Company's investments			4,589,000	6,248,000
Unrealized losses of hedge instruments			13,070,000	2,833,000
Foreign exchange risk exposure fair value			$ 1,000	$ 40,000