Derivative Instruments and Hedging Activities - Effect of Derivative Financial Instruments on Comprehensive Income (Detail) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2016	Mar. 31, 2015
Cash Flow Hedges \| Interest Expense \| Interest Rate Swaps
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in OCI on Derivatives (Effective Portion)	$ (1,625)	$ (1,168)
Amount of Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	0	0
Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Income (Loss) Recognized in Earnings	(195)	195
Not Designated as Hedging Instrument \| Other Non-interest Income \| Interest Rate Swaps
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Income (Loss) Recognized in Earnings	(472)	121
Not Designated as Hedging Instrument \| Other Non-interest Income \| Credit Contract
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Income (Loss) Recognized in Earnings	249	30
Not Designated as Hedging Instrument \| Mortgage Banking Income \| Residential Mortgage Loan Commitments
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Income (Loss) Recognized in Earnings	$ 28	$ 44

Derivative Instruments Gain Loss Recognized In Accumulated Other Comprehensive Income Net

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- Definition

Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5618551-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (a),(c),(d),(e)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624171-113959

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- Definition

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.

+ References

No definition available.

+ Details

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- Definition

The effective portion of loss reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624171-113959

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