Allowance for Loan Losses and Credit Quality Information - Schedule of Commercial Credit Exposure (Parenthetical) (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired non-impaired loans	$ 330,660	$ 371,100	$ 129,858
Total Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired non-impaired loans	$ 249,200	$ 277,000

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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