Loans - Average Recorded Investment and Interest Income on Impaired Loans (Detail) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2017	Mar. 31, 2016
Accounts, Notes, Loans and Financing Receivable
Average Recorded Investment	$ 113,768	$ 136,493
Interest Income Recognized	899	1,152
Commercial and industrial
Accounts, Notes, Loans and Financing Receivable
Average Recorded Investment	30,459	28,331
Interest Income Recognized	308	240
Commercial real estate loans
Accounts, Notes, Loans and Financing Receivable
Average Recorded Investment	58,021	82,200
Interest Income Recognized	343	687
Commercial real estate loans \| Commercial real estate
Accounts, Notes, Loans and Financing Receivable
Average Recorded Investment	55,325	72,398
Interest Income Recognized	324	639
Commercial real estate loans \| Construction
Accounts, Notes, Loans and Financing Receivable
Average Recorded Investment	2,696	9,802
Interest Income Recognized	19	48
Residential mortgage
Accounts, Notes, Loans and Financing Receivable
Average Recorded Investment	20,393	23,603
Interest Income Recognized	208	202
Consumer
Accounts, Notes, Loans and Financing Receivable
Average Recorded Investment	4,895	2,359
Interest Income Recognized	40	23
Consumer \| Home equity
Accounts, Notes, Loans and Financing Receivable
Average Recorded Investment	4,895	2,359
Interest Income Recognized	$ 40	$ 23

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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=66008989&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=66008989&loc=d3e5258-111524

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- Definition

Amount of interest income recognized on a cash-basis method of accounting that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

+ References

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