v3.8.0.1

Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - Assets and Liabilities Measured at Fair Value on a Recurring Basis [Member] - USD ($) $ in Thousands | Sep. 30, 2017 | Sep. 30, 2016
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Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items] |  |
Assets measured at fair value | $ 38,441 | $ 44,114
Liabilities measured at fair value | (14,864) | (14,517)
Available-for-sale securities [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items] |  |
Assets measured at fair value | 31,802 | 21,954
Cash equivalents [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items] |  |
Assets measured at fair value | 6,639 | 22,160
Contingent consideration [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items] |  |
Liabilities measured at fair value | (14,864) | (14,517)
Significant Other Observable Inputs (Level 2) [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items] |  |
Assets measured at fair value | 38,441 | 44,114
Significant Other Observable Inputs (Level 2) [Member] | Available-for-sale securities [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items] |  |
Assets measured at fair value | 31,802 | 21,954
Significant Other Observable Inputs (Level 2) [Member] | Cash equivalents [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items] |  |
Assets measured at fair value | 6,639 | 22,160
Significant Unobservable Inputs (Level 3) [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items] |  |
Liabilities measured at fair value | (14,864) | (14,517)
Significant Unobservable Inputs (Level 3) [Member] | Contingent consideration [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items] |  |
Liabilities measured at fair value | $ (14,864) | $ (14,517)

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- Definition Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258 + Details
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Definition Fair value of financial and nonfinancial obligations. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258 + Details
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