Disclosures about Fair Value of Assets and Liabilities - Qualitative Information about Unobservable Inputs Used in Recurring and Nonrecurring Level 3 Fair Value Measurements, Other than Goodwill (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount rate	10.00%
Significant Unobservable Inputs (Level 3) [Member] | Impaired loans [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value	$ 6,114	$ 8,652
Valuation Technique	Collateral based measurement	Collateral based measurement
Unobservable Inputs	Discount to reflect current market conditions and ultimate collectability	Discount to reflect current market conditions and ultimate collectability
Significant Unobservable Inputs (Level 3) [Member] | Mortgage servicing rights [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value	$ 7,039	$ 5,145
Valuation Technique	Discounted cashflows	Discounted cashflows
Unobservable Inputs	Discount rate, Constant prepayment rate, Probably of default	Discount rate, Constant prepayment rate, Probably of default
Minimum [Member] | Significant Unobservable Inputs (Level 3) [Member] | Impaired loans [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount to reflect current market conditions and ultimate collectability	10.00%	10.00%
Constant prepayment rate	4.00%	4.00%
Minimum [Member] | Significant Unobservable Inputs (Level 3) [Member] | Mortgage servicing rights [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount rate	10.00%	10.00%
Probably of default	1.00%	1.00%
Maximum [Member] | Significant Unobservable Inputs (Level 3) [Member] | Impaired loans [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount to reflect current market conditions and ultimate collectability	15.00%	15.00%
Constant prepayment rate	7.00%	7.00%
Maximum [Member] | Significant Unobservable Inputs (Level 3) [Member] | Mortgage servicing rights [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount rate	15.00%	15.00%
Probably of default	10.00%	10.00%
Weighted Average [Member] | Significant Unobservable Inputs (Level 3) [Member] | Impaired loans [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount to reflect current market conditions and ultimate collectability	12.00%	12.00%
Constant prepayment rate	4.60%	4.60%
Weighted Average [Member] | Significant Unobservable Inputs (Level 3) [Member] | Mortgage servicing rights [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount rate	12.00%	12.00%
Probably of default	4.50%	4.50%