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Business And Summary Of Significant Accounting Policies (Narrative) (Details) $ / shares in Units, shares in Thousands | 1 Months Ended | 12 Months Ended
--- | --- | ---
Nov. 30, 2018 $ / shares shares | Oct. 31, 2018 $ / shares shares | Sep. 30, 2018 $ / shares shares | Aug. 31, 2018 $ / shares shares | Aug. 31, 2019 USD ($) store segment warehouse | Sep. 01, 2018 USD ($) | Sep. 02, 2017 USD ($)
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |
Number of branch offices | store |  |  |  |  | 99 |  |
Number of customer fulfillment centers | warehouse |  |  |  |  | 12 |  |
Cash equivalents |  |  |  |  | $ 0 | $ 0 |
Amortization expense |  |  |  |  | 11,746,000 | 10,513,000 | $ 8,223,000
Impairment loss |  |  |  |  | 0 | 0 | 0
Deferred principal catalog costs |  |  |  |  | $ 3,363,000 | 3,973,000 |
Period deferred principal catalog costs remain the most current source of sales |  |  |  |  | 1 year |  |
Advertising costs |  |  |  |  | $ 18,812,000 | 15,530,000 | 16,289,000
Shipping and handling costs |  |  |  |  | 138,242,000 | 130,340,000 | 119,979,000
Purchases of treasury stock |  |  |  |  | 84,611,000 | 82,369,000 | $ 49,182,000
Unrecognized tax benefit that would affect effective tax rate |  |  |  |  | $ 11,698,000 | 9,407,000 |
Number of Operating Segments | segment |  |  |  |  | 1 |  |
Number of reportable segments | segment |  |  |  |  | 1 |  |
Class A Common Stock [Member] |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |
Repurchases of common stock, Shares | shares | 123 | 2 | 113 | 45 |  |  |
Cost of repurchase, per share | $ / shares | $ 81.22 | $ 85.00 | $ 84.29 | $ 82.64 |  |  |
Minimum [Member] |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |
Original manufacturers warranty period |  |  |  |  | 30 days |  |
Minimum [Member] | Accounting Standards Update 2016-02 [Member] |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |
Estimated effect of accounting change |  |  |  |  | $ 55,000,000 |  |
Maximum [Member] |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |
Warranty period |  |  |  |  | 1 year |  |
Original manufacturers warranty period |  |  |  |  | 90 days |  |
Maximum [Member] | Accounting Standards Update 2016-02 [Member] |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |
Estimated effect of accounting change |  |  |  |  | $ 65,000,000 |  |
Net Sales [Member] | Geographic Concentration Risk [Member] |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |
Concentration risk, percentage |  |  |  |  | 100.00% |  |
Net Sales [Member] | Geographic Concentration Risk [Member] | U.K., Canada, and Mexico [Member] |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |
Concentration risk, percentage |  |  |  |  | 4.00% |  |
Leasehold Improvements And Buildings [Member] | Minimum [Member] |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |
Property, plant and equipment estimated useful life |  |  |  |  | 3 years |  |
Leasehold Improvements And Buildings [Member] | Maximum [Member] |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |
Property, plant and equipment estimated useful life |  |  |  |  | 40 years |  |
Computer Systems, Equipment And Software [Member] | Minimum [Member] |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |
Property, plant and equipment estimated useful life |  |  |  |  | 3 years |  |
Computer Systems, Equipment And Software [Member] | Maximum [Member] |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |
Property, plant and equipment estimated useful life |  |  |  |  | 10 years |  |
Furniture, Fixtures And Equipment [Member] | Minimum [Member] |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |
Property, plant and equipment estimated useful life |  |  |  |  | 3 years |  |
Furniture, Fixtures And Equipment [Member] | Maximum [Member] |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |
Property, plant and equipment estimated useful life |  |  |  |  | 20 years |  |
Trademarks [Member] |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |
Impairment of intangible assets |  |  |  |  | $ 107,000 | 129,000 |
Customer Relationships And Trademarks [Member] |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |
Intangible assets acquired during period |  |  |  |  | 6,200,000 | $ 23,285,000 |
Contract Rights [Member] |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |
Write off of fully amortized assets |  |  |  |  | $ 23,100,000 |  |

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