LOANS - Commercial and Consumer Credit Exposure by Risk Attribute (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment [Line Items]
Commercial and industrial	$ 1,912,743	$ 1,781,948
Real Estate - Construction	467,730	399,434
Real Estate - Commercial	2,490,091	2,427,577
Lease financing	89,347	93,108
Total Commercial	4,959,911	4,702,067
Pass
Financing Receivable, Recorded Investment [Line Items]
Commercial and industrial	1,882,464	1,725,451
Real Estate - Construction	467,687	398,155
Real Estate - Commercial	2,446,999	2,349,662
Lease financing	88,078	92,540
Total Commercial	4,885,228	4,565,808
Special Mention
Financing Receivable, Recorded Investment [Line Items]
Commercial and industrial	6,226	18,256
Real Estate - Construction	0	1,258
Real Estate - Commercial	4,436	15,584
Lease financing	0	108
Total Commercial	10,662	35,206
Substandard
Financing Receivable, Recorded Investment [Line Items]
Commercial and industrial	24,053	38,241
Real Estate - Construction	43	21
Real Estate - Commercial	38,656	62,331
Lease financing	1,269	460
Total Commercial	64,021	101,053
Doubtful
Financing Receivable, Recorded Investment [Line Items]
Commercial and industrial	0	0
Real Estate - Construction	0	0
Real Estate - Commercial	0	0
Lease financing	0	0
Total Commercial	0	0
Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, before Fees, Gross	471,391	500,980
Residential Real Estate [Member] \| Performing
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, before Fees, Gross	463,459	491,380
Residential Real Estate [Member] \| Nonperforming
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, before Fees, Gross	7,932	9,600
Home Equity Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, before Fees, Gross	493,604	460,388
Home Equity Loan [Member] \| Performing
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, before Fees, Gross	489,148	456,314
Home Equity Loan [Member] \| Nonperforming
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, before Fees, Gross	4,456	4,074
Consumer Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, before Fees, Gross	41,586	50,639
Consumer Loan [Member] \| Performing
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, before Fees, Gross	41,331	50,202
Consumer Loan [Member] \| Nonperforming
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, before Fees, Gross	255	437
Credit card
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, before Fees, Gross	46,691	43,408
Credit card \| Performing
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, before Fees, Gross	46,691	43,408
Credit card \| Nonperforming
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, before Fees, Gross	0	0
Installment
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, before Fees, Gross	1,053,272	1,055,415
Installment \| Performing
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, before Fees, Gross	1,040,629	1,041,304
Installment \| Nonperforming
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, before Fees, Gross	$ 12,643	$ 14,111

Loans and Leases Receivable, Gross, Total of Commercial, Consumer Real Estate/Construction and Commercial Mortgage

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Amount before allowance of commercial leases and leveraged lease transactions where the entity is long-term creditor. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes leases covered under loss sharing agreements.

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Amount, before allowance and fees, of loans and leases receivable. Excludes loans and leases covered under loss sharing agreements.

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Amount before allowance of loans issued to commercial and industrial institutions. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes real estate loans and loans covered under loss sharing agreements.

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Amount before allowance of commercial construction loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans covered under loss sharing agreements.

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Amount before allowance of mortgage loans on existing land or building. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans covered under loss sharing agreements.

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