Reduction in Branch Network - Summary of Non Cash Amounts Recognized in Balance Sheet (Detail) (USD $)	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Assets
Cash and cash equivalents	$ 101,385,000	$ 102,952,000	$ 223,017,000	$ 188,073,000
Other loans held for sale	776,000	14,178,000
Liabilities
Time deposits	339,044,000	198,200,000
Total deposits	1,023,242,000	1,064,181,000
Branches Under Contract For Sale [Member]
Assets
Cash and cash equivalents	643,000
Other loans held for sale	7,508,000
Long-lived assets held for sale	664,000
Liabilities
Transaction deposits	12,641,000
Money market deposits	3,550,000
Savings deposits	2,141,000
Time deposits	22,763,000
Total deposits	$ 41,095,000