Loans and Other Real Estate - Composition of Company`s Loan and Lease Portfolio (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 4,925,998	$ 4,460,447
Less: deferred fees	(2,584)	(3,714)
Loans, net of deferred fees	4,923,414	4,456,733
Commercial, secured by real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	3,442,973	3,057,779
Commercial, industrial and other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	391,486	336,735
Equipment finance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	104,689	87,925
Real estate - residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	337,482	329,854
Real estate - construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	306,440	319,545
Home equity and consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 342,928	$ 328,609

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Amount of deferred interest and fee income, unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of acquired loans. Excludes amounts for loans and leases covered under loss sharing agreements.

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Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

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Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

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