Loans and Allowance for Loan Losses - Summary of Troubled Debt Restructurings by Class of Loans (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013 Contract	Dec. 31, 2012 Contract
Financing Receivable, Modifications [Line Items]
Number of Contracts	520	498
Pre-Modification Outstanding Recorded Investment	$ 11,366	$ 10,947
Post-Modification Outstanding Recorded Investment	10,175	11,805
Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	10	21
Pre-Modification Outstanding Recorded Investment	4,439	4,067
Post-Modification Outstanding Recorded Investment	3,588	4,505
Commercial and Industrial [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts		8
Pre-Modification Outstanding Recorded Investment		389
Post-Modification Outstanding Recorded Investment		257
Total Commercial Loans and Leases [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	10	29
Pre-Modification Outstanding Recorded Investment	4,439	4,456
Post-Modification Outstanding Recorded Investment	3,588	4,762
Direct Installment [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	409	362
Pre-Modification Outstanding Recorded Investment	4,198	3,876
Post-Modification Outstanding Recorded Investment	3,971	3,763
Residential Mortgages [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	54	56
Pre-Modification Outstanding Recorded Investment	2,464	2,232
Post-Modification Outstanding Recorded Investment	2,366	2,814
Indirect Installment [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	28	31
Pre-Modification Outstanding Recorded Investment	117	169
Post-Modification Outstanding Recorded Investment	107	151
Consumer Lines of Credit [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	19	20
Pre-Modification Outstanding Recorded Investment	148	214
Post-Modification Outstanding Recorded Investment	$ 143	$ 315