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Stockholders' Equity - Summary of Shares Repurchased Under Stock Purchase Program (Detail) - $ / shares | 3 Months Ended |  |
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Mar. 31, 2016 | Mar. 31, 2017 | Sep. 30, 2016
Summary Of Shares Repurchased Under Stock Purchase Program [Abstract] |  |  |
Number of shares repurchased | 100,000 |  |
Average price of shares repurchased | $ 55.23 |  |
Shares remaining to be repurchased | 66,276 | 150,000 | 150,000

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- Definition Summary of shares repurchased under stock purchase program. + References No definition available. + Details
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- Definition Number of stock bought back by the entity at the exercise price or redemption price. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644 + Details
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- Definition The remaining number of shares authorized to be repurchased by an entity's Board of Directors under a stock repurchase plan. + 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://www.xbrl.org/2003/role/presentationRef -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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