Rent Commitments, Before Considering Renewal Options (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012
Lease and Rental Expense [Line Items]
2013	$ 339
2014	178
2015	220
2016	230
2017	237
Thereafter	893
Total	2,097
Premises
Lease and Rental Expense [Line Items]
2013	311
2014	178
2015	220
2016	230
2017	237
Thereafter	893
Total	2,069
Equipment
Lease and Rental Expense [Line Items]
2013	28
2014	0
2015	0
2016	0
2017	0
Thereafter	0
Total	$ 28