Derivative Financial Instruments - Schedule of Notional Amounts and Estimated Fair Values of Interest Rate Derivative Contracts Outstanding (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Designated as Hedging Instrument [Member] \| Financial institution counterparties Loan/lease interest rate swaps assets [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	$ 10,642	$ 10,941
Estimated Fair Value	141	207
Designated as Hedging Instrument [Member] \| Financial institution counterparties Loan/lease interest rate swaps liabilities [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	3,538	3,885
Estimated Fair Value	(185)	(199)
Non Designated as Hedging Instrument [Member] \| Financial institution counterparties Loan/lease interest rate swaps assets [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	363,454	496,887
Estimated Fair Value	1,343	2,384
Non Designated as Hedging Instrument [Member] \| Financial institution counterparties Loan/lease interest rate swaps liabilities [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	748,152	691,143
Estimated Fair Value	(12,868)	(8,921)
Non Designated as Hedging Instrument [Member] \| Financial institution counterparties Loan/lease interest-rate caps assets [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	143,084	122,791
Estimated Fair Value	688	509
Non Designated as Hedging Instrument [Member] \| Customer counterparties Loan/lease interest rate swaps assets [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	764,546	691,143
Estimated Fair Value	24,818	16,706
Non Designated as Hedging Instrument [Member] \| Customer counterparties Loan/lease interest rate swaps liabilities [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	347,060	496,887
Estimated Fair Value	(3,503)	(8,891)
Non Designated as Hedging Instrument [Member] \| Customer counterparties Loan/lease interest rate caps liabilities [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	143,084	122,791
Estimated Fair Value	$ (688)	$ (509)

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

+ Details

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- Definition

Fair value of the assets less the liabilities of a derivative or group of derivatives.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13433-108611

+ Details

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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.

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