Earnings Per Share - Additional Information (Detail) - shares	Sep. 30, 2015	Aug. 31, 2015	May. 31, 2008
Equity [Abstract]
Common stock shares authorized for repurchase		2,000,000	2,000,000
Shares remain authorized for repurchase	2,143,711

The remaining number of shares authorized to be repurchased by an entity's Board of Directors under a stock repurchase plan.

No definition available.

Name:	us-gaap_StockRepurchaseProgramRemainingNumberOfSharesAuthorizedToBeRepurchased
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant