Stockholders' Equity - Additional Information (Detail) - Stock Repurchase Program - USD ($)	Sep. 30, 2017	May 18, 2017	Jun. 02, 2016
Stockholders Equity [Line Items]
Board of Directors authorized stock repurchase program		$ 200,000,000	$ 100,000,000
Board of Directors authorized additional stock repurchase program		$ 100,000,000
Available amount under repurchase program	$ 26,100,000

Amount remaining of a stock repurchase plan authorized.

No definition available.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant