Loans - Average Recorded Investment and Interest Income on Impaired Loans (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Accounts, Notes, Loans and Financing Receivable
Average Recorded Investment	$ 131,515	$ 130,371	$ 122,642	$ 133,432
Interest Income Recognized	1,009	976	1,909	2,128
Commercial and industrial
Accounts, Notes, Loans and Financing Receivable
Average Recorded Investment	46,283	24,157	38,371	26,244
Interest Income Recognized	288	194	596	434
Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable
Average Recorded Investment	62,878	80,221	60,450	81,211
Interest Income Recognized	503	528	847	1,215
Commercial Real Estate \| Commercial real estate
Accounts, Notes, Loans and Financing Receivable
Average Recorded Investment	60,119	70,194	57,722	71,296
Interest Income Recognized	483	475	808	1,114
Commercial Real Estate \| Construction
Accounts, Notes, Loans and Financing Receivable
Average Recorded Investment	2,759	10,027	2,728	9,915
Interest Income Recognized	20	53	39	101
Residential mortgage
Accounts, Notes, Loans and Financing Receivable
Average Recorded Investment	17,555	22,922	18,974	23,262
Interest Income Recognized	184	234	392	436
Consumer
Accounts, Notes, Loans and Financing Receivable
Average Recorded Investment	4,799	3,071	4,847	2,715
Interest Income Recognized	34	20	74	43
Consumer \| Home equity
Accounts, Notes, Loans and Financing Receivable
Average Recorded Investment	4,799	3,071	4,847	2,715
Interest Income Recognized	$ 34	$ 20	$ 74	$ 43

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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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