Loans and Allowance for Loan Losses - Summary of Impaired Loans, by Class (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Financial Receivables Impaired Or Restructured [Line Items]
Recorded Investment	$ 3,728
Related Allowance	825
Commercial Real Estate [Member]
Financial Receivables Impaired Or Restructured [Line Items]
With no allowance recorded, Recorded Investment	40,472	37,119
With no allowance recorded, Unpaid Principal Balance	62,034	50,234
With no allowance recorded, Related Allowance
With no allowance recorded, Average Recorded Investment	37,376	36,426
With allowance recorded, Recorded Investment	3,603	12,623
With allowance recorded, Unpaid Principal Balance	3,818	21,877
With allowance recorded, Specific Related Allowance	701	2,136
With allowance recorded, Average Recorded Investment	14,379	14,522
Recorded Investment	44,075	49,742
Unpaid Principal Balance	65,852	72,111
Related Allowance	701	2,136
Average Recorded Investment	51,755	50,948
Commercial and Industrial [Member]
Financial Receivables Impaired Or Restructured [Line Items]
With no allowance recorded, Recorded Investment	7,301	7,074
With no allowance recorded, Unpaid Principal Balance	8,669	9,597
With no allowance recorded, Average Recorded Investment	8,304	6,992
With allowance recorded, Recorded Investment	122	590
With allowance recorded, Unpaid Principal Balance	130	590
With allowance recorded, Specific Related Allowance	123	590
With allowance recorded, Average Recorded Investment	126	592
Recorded Investment	7,423	7,664
Unpaid Principal Balance	8,799	10,187
Related Allowance	123	590
Average Recorded Investment	8,430	7,584
Commercial Leases [Member]
Financial Receivables Impaired Or Restructured [Line Items]
With no allowance recorded, Recorded Investment	734	965
With no allowance recorded, Unpaid Principal Balance	734
With no allowance recorded, Average Recorded Investment	758	1,053
Recorded Investment	734	965
Unpaid Principal Balance	734
Average Recorded Investment	758	1,053
Total Commercial Loans and Leases [Member]
Financial Receivables Impaired Or Restructured [Line Items]
With no allowance recorded, Recorded Investment	48,507	45,158
With no allowance recorded, Unpaid Principal Balance	71,437	59,831
With no allowance recorded, Average Recorded Investment	46,438	44,471
With allowance recorded, Recorded Investment	3,725	13,213
With allowance recorded, Unpaid Principal Balance	3,948	22,467
With allowance recorded, Specific Related Allowance	824	2,726
With allowance recorded, Average Recorded Investment	14,505	15,114
Recorded Investment	52,232	58,371
Unpaid Principal Balance	75,385	82,298
Related Allowance	824	2,726
Average Recorded Investment	60,943	59,585
Direct Installment [Member]
Financial Receivables Impaired Or Restructured [Line Items]
With no allowance recorded, Recorded Investment	10,577	8,541
With no allowance recorded, Unpaid Principal Balance	10,830	8,693
With no allowance recorded, Average Recorded Investment	10,557	6,443
Recorded Investment	10,577	8,541
Unpaid Principal Balance	10,830	8,693
Average Recorded Investment	10,557	6,443
Residential Mortgages [Member]
Financial Receivables Impaired Or Restructured [Line Items]
With no allowance recorded, Recorded Investment	14,012	11,414
With no allowance recorded, Unpaid Principal Balance	14,560	11,223
With no allowance recorded, Average Recorded Investment	13,565	9,059
Recorded Investment	14,012	11,414
Unpaid Principal Balance	14,560	11,223
Average Recorded Investment	13,565	9,059
Indirect Installment [Member]
Financial Receivables Impaired Or Restructured [Line Items]
With no allowance recorded, Recorded Investment	1,202	1,132
With no allowance recorded, Unpaid Principal Balance	2,633	2,381
With no allowance recorded, Average Recorded Investment	1,127	1,133
Recorded Investment	1,202	1,132
Unpaid Principal Balance	2,633	2,381
Average Recorded Investment	1,127	1,133
Consumer Lines of Credit [Member]
Financial Receivables Impaired Or Restructured [Line Items]
With no allowance recorded, Recorded Investment	597	746
With no allowance recorded, Unpaid Principal Balance	668	792
With no allowance recorded, Average Recorded Investment	573	591
Recorded Investment	597	746
Unpaid Principal Balance	668	792
Average Recorded Investment	573	591
Other [Member]
Financial Receivables Impaired Or Restructured [Line Items]
With no allowance recorded, Recorded Investment		3,500
With no allowance recorded, Unpaid Principal Balance		3,500
With no allowance recorded, Average Recorded Investment		3,500
Recorded Investment		3,500
Unpaid Principal Balance		3,500
Average Recorded Investment		$ 3,500