Fair Value - Schedule of Fair Value Level III Assets Measured at Fair Value on a Recurring or Non-Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Dec. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Valuation Technique	Appraisal of collateral
Impaired Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value of Assets	$ 16,568	$ 14,740
Valuation Technique	Discounted Cash Flow
Significant Unobservable Inputs	Remaining term
Range	.4 yrs to 21.5 yrs
Servicing Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value of Assets	9	14
Valuation Technique	Discounted Cash Flow
Significant Unobservable Inputs	Remaining term
Range	.2 yrs to 18.5 yrs
Real Estate Acquired Through Foreclosure [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value of Assets	1,944	2,441
Valuation Technique	Appraisal of collateral (1)
Trust Preferred Securities Credit Spreads [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Significant Unobservable Inputs	Credit Spreads
Range	45-75 basis points
Trust Preferred Securities Liquidity Risk Adjustments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Significant Unobservable Inputs	Liquidity Risk Adjustments
Range	20-55 basis points
Trust Preferred Securities Default Rates [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Significant Unobservable Inputs	Default Rates
Range	.6% -1%
Impaired Loans Discount Rate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Significant Unobservable Inputs	Discount Rate
Range	3.8%-7.0%
Impaired Loans Appraisal Adjustment and Liquidation Expense [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Significant Unobservable Inputs	Appraisal adj and liquidation exp
Range	2,000-500,000
Servicing Assets Discount Rate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Significant Unobservable Inputs	Discount Rate
Range	11.25%-12.25%
Trust Preferred Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value of Assets	$ 36,934	$ 36,179
Valuation Technique	Discounted Cash Flow