Disclosures about Fair Value of Assets and Liabilities - Realized Gains and Losses included in Net Income for Periods in Condensed Consolidated Statements of Income (Detail) (Non Interest Income [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Included in net income	$ 240	$ (12)
Hedged Loans [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Included in net income	207	(401)
Fair value interest rate swap agreements [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Included in net income	(207)	401
Derivative loan commitments [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Included in net income	$ 240	$ (12)