Loans and Allowance for Loan Losses - Impaired Loans (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded Investment, Total	$ 21,511	$ 26,167	$ 33,592
Unpaid Principal Balance, Total	27,317	34,156	43,110
Related Allowance, Total	938	1,673	3,932
Average Recorded Balance, Total	24,579	28,382	35,466
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded Investment	15,530	15,378	12,585
Unpaid Principal Balance	20,438	20,086	20,138
Related Allowance	0	0	0
Average Recorded Balance	16,705	9,945	14,805
Recorded Investment	2,312	7,942	19,161
Unpaid Principal Balance	2,319	9,876	19,823
Related Allowance	865	1,449	3,747
Average Recorded Balance	4,374	16,571	18,130
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded Investment	214	138	386
Unpaid Principal Balance	267	138	386
Related Allowance	0	0	0
Average Recorded Balance	186	207	419
Recorded Investment	258	459	319
Unpaid Principal Balance	258	459	794
Related Allowance	73	209	148
Average Recorded Balance	346	251	570
Residential real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded Investment	1,731	1,610	1,069
Unpaid Principal Balance	1,940	1,686	1,897
Related Allowance	0	0	0
Average Recorded Balance	1,832	1,187	1,470
Recorded Investment	0	181	72
Unpaid Principal Balance	0	1,452	72
Related Allowance	0	15	37
Average Recorded Balance	0	106	72
Home equity loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded Investment	1,111	398	0
Unpaid Principal Balance	1,623	398	0
Related Allowance	0	0	0
Average Recorded Balance	847	100	0
Recorded Investment	0	0	0
Unpaid Principal Balance	0	0	0
Related Allowance	0	0	0
Average Recorded Balance	0	0	0
Indirect
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded Investment	195	0	0
Unpaid Principal Balance	268	0	0
Related Allowance	0	0	0
Average Recorded Balance	178	0	0
Recorded Investment	0	0	0
Unpaid Principal Balance	0	0	0
Related Allowance	0	0	0
Average Recorded Balance	0	0	0
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded Investment	160	61	0
Unpaid Principal Balance	204	61	0
Related Allowance	0	0	0
Average Recorded Balance	111	15	0
Recorded Investment	0	0	0
Unpaid Principal Balance	0	0	0
Related Allowance	0	0	0
Average Recorded Balance	$ 0	$ 0	$ 0