Loans and Leases - Summary of Impaired Loans and Lease, by Class (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Financial Receivables Impaired Or Restructured [Line Items]
Unpaid Contractual Principal Balance	$ 104,086	$ 84,525
Recorded Investment With No Specific Reserve	70,107	64,374
Recorded Investment With Specific Reserve	20,242	6,315
Total Recorded Investment	90,349	70,689
Specific Reserve	9,645	2,650
Average Recorded Investment	87,601	68,950
Commercial Real Estate [Member]
Financial Receivables Impaired Or Restructured [Line Items]
Unpaid Contractual Principal Balance	20,836	33,780
Recorded Investment With No Specific Reserve	15,057	24,423
Recorded Investment With Specific Reserve	3,214	772
Total Recorded Investment	18,271	25,195
Specific Reserve	550	321
Average Recorded Investment	21,677	26,143
Commercial and Industrial [Member]
Financial Receivables Impaired Or Restructured [Line Items]
Unpaid Contractual Principal Balance	41,296	15,860
Recorded Investment With No Specific Reserve	18,654	9,176
Recorded Investment With Specific Reserve	17,028	5,543
Total Recorded Investment	35,682	14,719
Specific Reserve	9,095	2,329
Average Recorded Investment	31,603	12,298
Commercial Leases [Member]
Financial Receivables Impaired Or Restructured [Line Items]
Unpaid Contractual Principal Balance	3,359	659
Recorded Investment With No Specific Reserve	3,359	659
Total Recorded Investment	3,359	659
Average Recorded Investment	1,514	747
Total Commercial Loans and Leases [Member]
Financial Receivables Impaired Or Restructured [Line Items]
Unpaid Contractual Principal Balance	65,491	50,299
Recorded Investment With No Specific Reserve	37,070	34,258
Recorded Investment With Specific Reserve	20,242	6,315
Total Recorded Investment	57,312	40,573
Specific Reserve	9,645	2,650
Average Recorded Investment	54,794	39,188
Direct Installment [Member]
Financial Receivables Impaired Or Restructured [Line Items]
Unpaid Contractual Principal Balance	16,465	14,679
Recorded Investment With No Specific Reserve	15,072	13,792
Total Recorded Investment	15,072	13,792
Average Recorded Investment	14,972	13,267
Residential Mortgages [Member]
Financial Receivables Impaired Or Restructured [Line Items]
Unpaid Contractual Principal Balance	14,049	13,394
Recorded Investment With No Specific Reserve	13,399	12,763
Total Recorded Investment	13,399	12,763
Average Recorded Investment	13,164	12,896
Indirect Installment [Member]
Financial Receivables Impaired Or Restructured [Line Items]
Unpaid Contractual Principal Balance	4,668	3,745
Recorded Investment With No Specific Reserve	1,926	1,514
Total Recorded Investment	1,926	1,514
Average Recorded Investment	1,846	1,401
Consumer Lines of Credit [Member]
Financial Receivables Impaired Or Restructured [Line Items]
Unpaid Contractual Principal Balance	3,413	2,408
Recorded Investment With No Specific Reserve	2,640	2,047
Total Recorded Investment	2,640	2,047
Average Recorded Investment	$ 2,825	$ 2,198