Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements - Additional Information (Detail)

v3.3.0.814
Fair Value Measurements - Additional Information (Detail) - USD ($)
Sep. 30, 2015
Jun. 30, 2015
Dec. 31, 2014
Sep. 30, 2014
Jun. 30, 2014
Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Loans held for sale $ 4,871,000 $ 4,158,000 $ 5,451,000 $ 7,757,000 $ 3,842,000 $ 0
Investment in FRB stock 14,098,000   12,273,000      
Minimum [Member]            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Unpaid principal balance of Non-accrual Non-PCI loans reviewed individually for amount of impairment 100,000          
Maximum [Member]            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Unpaid principal balance of Non-accrual Non-PCI loans reviewed collectively for amount of impairment 100,000          
Fair Value, Inputs, Level 2 [Member] | Fair Value [Member]            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Investment in FHLB stock 16,385,000   17,580,000      
Investment in FRB stock 14,098,000   12,273,000      
Fair Value, Inputs, Level 2 [Member] | Non-recurring Basis [Member] | Non-Performing Loans Held for Sale [Member]            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Loans held for sale 0   0      
Fair Value, Inputs, Level 2 [Member] | Non-recurring Basis [Member] | Small Business Administration Loans Held for Sale [Member]            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Loans held for sale $ 4,900,000   $ 5,500,000