Fair Values - Reconciliation of Assets and Liabilities Measured at Fair Value Significant Unobservable Inputs Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013 Obligations of States and Political Subdivisions [Member]	Sep. 30, 2013 Mortgage Backed Securities [Member]	Sep. 30, 2012 Derivatives - interest rate lock commitments [Member]	Sep. 30, 2012 Earn out payable [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	$ 1,131	$ 13,747	$ 179	$ 600
Transfers into Level 3			0	0
Change included in earnings	0	0	52	0
Purchases and issuances	0	0	0	0
Sales and Settlements	0	(749)	(231)	(600)
Transfers out	(1,131)	(12,998)	0	0
Ending balance	0	0	0	0
Net change in unrealized gains or (losses) relating to items held at end of period	$ 0	$ 0	$ 0	$ 0