Loans and Leases - Summary of Impaired Loans and Lease, by Class (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2016	Dec. 31, 2015
Financial Receivables Impaired Or Restructured [Line Items]
Unpaid Contractual Principal Balance	$ 96,412	$ 84,525
Recorded Investment With No Specific Reserve	68,850	64,374
Recorded Investment With Specific Reserve	13,999	6,315
Total Recorded Investment	82,849	70,689
Specific Reserve	6,012	2,650
Average Recorded Investment	75,992	68,950
Commercial Real Estate [Member]
Financial Receivables Impaired Or Restructured [Line Items]
Unpaid Contractual Principal Balance	33,434	33,780
Recorded Investment With No Specific Reserve	24,035	24,423
Recorded Investment With Specific Reserve	1,520	772
Total Recorded Investment	25,555	25,195
Specific Reserve	400	321
Average Recorded Investment	25,374	26,143
Commercial and Industrial [Member]
Financial Receivables Impaired Or Restructured [Line Items]
Unpaid Contractual Principal Balance	25,965	15,860
Recorded Investment With No Specific Reserve	12,042	9,176
Recorded Investment With Specific Reserve	12,479	5,543
Total Recorded Investment	24,521	14,719
Specific Reserve	5,612	2,329
Average Recorded Investment	19,620	12,298
Commercial Leases [Member]
Financial Receivables Impaired Or Restructured [Line Items]
Unpaid Contractual Principal Balance	894	659
Recorded Investment With No Specific Reserve	894	659
Total Recorded Investment	894	659
Average Recorded Investment		747
Total Commercial Loans and Leases [Member]
Financial Receivables Impaired Or Restructured [Line Items]
Unpaid Contractual Principal Balance	60,293	50,299
Recorded Investment With No Specific Reserve	36,971	34,258
Recorded Investment With Specific Reserve	13,999	6,315
Total Recorded Investment	50,970	40,573
Specific Reserve	6,012	2,650
Average Recorded Investment	44,994	39,188
Direct Installment [Member]
Financial Receivables Impaired Or Restructured [Line Items]
Unpaid Contractual Principal Balance	15,135	14,679
Recorded Investment With No Specific Reserve	14,141	13,792
Total Recorded Investment	14,141	13,792
Average Recorded Investment	13,966	13,267
Residential Mortgages [Member]
Financial Receivables Impaired Or Restructured [Line Items]
Unpaid Contractual Principal Balance	13,881	13,394
Recorded Investment With No Specific Reserve	13,351	12,763
Total Recorded Investment	13,351	12,763
Average Recorded Investment	13,058	12,896
Indirect Installment [Member]
Financial Receivables Impaired Or Restructured [Line Items]
Unpaid Contractual Principal Balance	3,667	3,745
Recorded Investment With No Specific Reserve	1,504	1,514
Total Recorded Investment	1,504	1,514
Average Recorded Investment	1,509	1,401
Consumer Lines of Credit [Member]
Financial Receivables Impaired Or Restructured [Line Items]
Unpaid Contractual Principal Balance	3,436	2,408
Recorded Investment With No Specific Reserve	2,883	2,047
Total Recorded Investment	2,883	2,047
Average Recorded Investment	$ 2,465	$ 2,198

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- Definition

Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=49124121&loc=d3e5212-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=49124121&loc=d3e5258-111524

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Amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 14A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=49124121&loc=SL6953550-111524

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