Unearned ESOP Shares - Additional Information (Detail) (USD $)	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Borrowed funds	$ 1,600,000
ESOP [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Compensation costs	$ 733,000	$ 717,000

Sum of the carrying values as of the balance sheet date of all debt, including all short-term borrowings, long-term debt, collateralized financings, and capital lease obligations.

No definition available.

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