Schedule of Gains (Losses) Recognized on Assets Measured at Fair Value on Non-Recurring Basis (Detail) (Fair Value, Measurements, Nonrecurring, USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Fair Value, Measurements, Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-performing loans receivable held-for-sale	$ (471)	$ 1
Impaired loans carried at fair value of collateral	(34)	(1,090)
Real estate owned	0	19
Total	$ (505)	$ (1,070)