Derivative Financial Instruments - Schedule of Derivative Financial Instruments on Statements of Income (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Derivative [Line Items]
Derivatives in hedging relationships	$ 14,847	$ 3,295	$ 9,885	$ 6,170
Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivatives in hedging relationships	(277)	(68)	(720)	(98)
Designated as Hedging Instrument [Member] \| Interest And Fees On Loans [Member] \| Interest Rate Contracts [Member] \| Fair Value Hedging [Member]
Derivative [Line Items]
Derivatives in hedging relationships	(277)	(68)	(720)	(98)
Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivatives not designated as hedging instruments	15,124	3,363	10,605	6,268
Not Designated as Hedging Instrument [Member] \| Income from Mortgage Banking Activities [Member] \| TBA Mortgage Backed Securities [Member]
Derivative [Line Items]
Derivatives not designated as hedging instruments	17,204	(962)	(1,771)	(474)
Not Designated as Hedging Instrument [Member] \| Income from Mortgage Banking Activities [Member] \| Interest Rate Lock Commitments [Member]
Derivative [Line Items]
Derivatives not designated as hedging instruments	(1,527)	3,833	12,169	5,870
Not Designated as Hedging Instrument [Member] \| Income from Mortgage Banking Activities [Member] \| Forward Loan Sale Commitments [Member]
Derivative [Line Items]
Derivatives not designated as hedging instruments	$ (553)	$ 492	$ 207	$ 872

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

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5618551-113959

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- Definition

Amount of realized and unrealized gain (loss) of derivative instruments not designated or qualifying as hedging instruments.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4CC
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL109998890-113959

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5624171-113959

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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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