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) (Significant Unobservable Inputs (Level 3) [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Impaired loans [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value	$ 6,023	$ 6,114
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
Mortgage servicing rights [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value	$ 7,030	$ 7,039
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] | 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] | 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] | 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] | 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] | 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] | 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%