Summary of Financial and Nonfinancial Assets Measured at Fair Value on a Nonrecurring Basis (Detail) (Fair Value on a Nonrecurring, USD $) In Thousands, unless otherwise specified	Jun. 30, 2013
Impaired Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fair value	$ 6,176
OREO | Not covered by loss share agreements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fair value	3,941
OREO | Covered by loss share agreements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fair value	4,423
Level 3 | Impaired Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fair value	6,176
Level 3 | OREO | Not covered by loss share agreements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fair value	3,941
Level 3 | OREO | Covered by loss share agreements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fair value	$ 4,423