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Subsequent Events (Details) - $ / shares shares in Thousands | 1 Months Ended | 3 Months Ended | 12 Months Ended
--- | --- | --- | ---
Oct. 31, 2018 | Sep. 30, 2018 | Jul. 31, 2018 | Sep. 01, 2018 | Sep. 03, 2016
Subsequent Event [Line Items] |  |  |  |  |
Cost of repurchase, per share |  |  | $ 82.64 |  |
Subsequent Event [Member] |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Shares repurchased and retired | 493 | 7 |  |  |
Cost of repurchase, per share | $ 81.22 | $ 85.00 |  |  |
Purchases From Class B Holders [Member] | Subsequent Event [Member] |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Shares repurchased and retired | 2 | 113 |  |  |
Cost of repurchase, per share | $ 85.00 | $ 84.29 |  |  |
Class A Common Stock [Member] |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Cost of repurchase, per share |  |  |  | $ 82.64 |
Class A Common Stock [Member] | Purchases From Class B Holders [Member] |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Shares repurchased and retired |  |  |  |  | 1,152
Cost of repurchase, per share |  |  |  |  | $ 72.50

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- Definition Number of shares that have been repurchased and retired during the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(28)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644 + Details
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- Definition Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event. + References No definition available. + Details
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- Definition Total cost of shares repurchased divided by the total number of shares repurchased. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 30 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6405813&loc=d3e23239-112655 + Details
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