Loans and Allowance for Loan Losses - Summary of Troubled Debt Restructurings by Class of Loans, Payment Default (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2014 Contract		Sep. 30, 2013 Contract		Sep. 30, 2014 Contract		Sep. 30, 2013 Contract
Financing Receivable, Modifications [Line Items]
Number of Contracts	47	[1]	27	[1]	87	[1]	65	[1]
Recorded Investment	$ 449	[1]	$ 438	[1]	$ 826	[1]	$ 1,637	[1]
Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts		[1]				[1]	1	[1]
Recorded Investment		[1]				[1]	751	[1]
Commercial and Industrial [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts		[1]				[1]	1	[1]
Recorded Investment		[1]				[1]	15	[1]
Commercial Leases [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts		[1]				[1]
Recorded Investment		[1]				[1]
Total Commercial Loans and Leases [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts		[1]				[1]	2	[1]
Recorded Investment		[1]				[1]	766	[1]
Direct Installment [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	41	[1]	24	[1]	80	[1]	53	[1]
Recorded Investment	356	[1]	254	[1]	732	[1]	509	[1]
Residential Mortgages [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	2	[1]	2	[1]	2	[1]	5	[1]
Recorded Investment	33	[1]	99	[1]	33	[1]	240	[1]
Indirect Installment [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	3	[1]			4	[1]	4	[1]
Recorded Investment	10	[1]			11	[1]	37	[1]
Consumer Lines of Credit [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	1	[1]	1	[1]	1	[1]	1	[1]
Recorded Investment	50	[1]	85	[1]	50	[1]	85	[1]
Other [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts		[1]				[1]
Recorded Investment		[1]				[1]

[1] The recorded investment is as of period end.