Assets Measured at Fair Value on Nonrecurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value disclosure, nonrecurring	$ 30,803		$ 49,550
Fair value measured on nonrecurring basis losses	(5,712)		(6,918)
Impaired loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value disclosure, nonrecurring	29,465	[1]	43,624	[1]
Fair value measured on nonrecurring basis losses	(5,403)	[1]	(6,730)	[1]
Other real estate owned
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value disclosure, nonrecurring	1,338		5,926
Fair value measured on nonrecurring basis losses	(309)		(188)
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value disclosure, nonrecurring	0		0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Impaired loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value disclosure, nonrecurring	0	[1]	0	[1]
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other real estate owned
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value disclosure, nonrecurring	0		0
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value disclosure, nonrecurring	0		0
Significant Other Observable Inputs (Level 2) | Impaired loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value disclosure, nonrecurring	0	[1]	0	[1]
Significant Other Observable Inputs (Level 2) | Other real estate owned
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value disclosure, nonrecurring	0		0
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value disclosure, nonrecurring	30,803		49,550
Significant Unobservable Inputs (Level 3) | Impaired loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value disclosure, nonrecurring	29,465	[1]	43,624	[1]
Significant Unobservable Inputs (Level 3) | Other real estate owned
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value disclosure, nonrecurring	$ 1,338		$ 5,926

[1] Amounts represent the fair value of collateral for impaired loans allocated to the allowance for loan and lease losses. Fair values are determined using actual market prices (Level 2), independent third party valuations and borrower records, discounted as appropriate (Level 3).