Loans Held for Sale - Additional Information (Detail) (USD $)	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Servicing Assets at Fair Value [Line Items]
Residential loans held for sale, at fair value	$ 13,572,000	$ 4,366,000	$ 12,591,000
Finance leases held for sale	11,553,000
Loss recognized due to transfer of leases	200,000
Average maturity of portfolio of leases held for sale	2 years 8 months 12 days
Proceeds from sale of loans	4,787,000	2,242,000
Minimum [Member]
Servicing Assets at Fair Value [Line Items]
Interest rate on portfolio of leases held for sale	3.57%
Maximum [Member]
Servicing Assets at Fair Value [Line Items]
Interest rate on portfolio of leases held for sale	10.22%
Commercial And Commercial Real Estate [Member]
Servicing Assets at Fair Value [Line Items]
Commercial and commercial real estate loans held for investment	3,600,000	1,600,000
Purchased impaired loans	400,000	1,500,000
Proceeds from sale of loans	4,800,000	2,200,000
Charge-offs	200,000	100,000
Other income	1,000,000
Income recognized on sale of loans	$ 400,000	$ 700,000