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	6 Months Ended	12 Months Ended
	Jun. 30, 2014	Dec. 31, 2013
Impaired loans [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value	$ 6,575	$ 6,114
Valuation Technique	Collateral based measurement
Unobservable Inputs	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	$ 7,313	$ 7,039
Valuation Technique	Discounted cashflows
Unobservable Inputs	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%