v3.8.0.1

Basis of Presentation - Additional Information (Detail) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2017 | Sep. 30, 2016 | Sep. 30, 2017 | Sep. 30, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |
Income tax expense | $ (1,622) | $ (2,799) | $ (9,324) | $ (5,515)
Accounting Standards Update 2016-09 [Member] |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |
Deferred tax liability | 1,000 |  | 1,000 |
Income tax expense |  |  | 1,600 |
Retained Earnings [Member] | Accounting Standards Update 2016-09 [Member] |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |
Cumulative effect adjustment | $ 1,000 |  | $ 1,000 |

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