Loans and Allowance for Loan Losses - Schedule of Recorded Investment in Residential and Consumer Loans Based on Payment Activity (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment, Past Due [Line Items]
Finance receivable recorded investment, Performing	$ 11,960,284	$ 12,037,323
Total loans and leases outstanding	12,117,524	12,243,892
Residential Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases outstanding	2,334,289	2,248,404
Residential Real Estate [Member] \| Performing Financing Receivable [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Finance receivable recorded investment, Performing	2,311,670	2,223,450
Residential Real Estate [Member] \| Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Finance receivable recorded investment, Nonperforming	22,619	24,954
Consumer Home Equity [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases outstanding	559,021	589,322
Consumer Home Equity [Member] \| Performing Financing Receivable [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Finance receivable recorded investment, Performing	555,025	586,235
Consumer Home Equity [Member] \| Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Finance receivable recorded investment, Nonperforming	3,996	3,087
Consumer Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases outstanding	1,017,287	1,059,633
Consumer Auto [Member] \| Performing Financing Receivable [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Finance receivable recorded investment, Performing	1,013,760	1,057,038
Consumer Auto [Member] \| Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Finance receivable recorded investment, Nonperforming	3,527	2,595
Consumer - Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases outstanding	149,839	154,712
Consumer - Other [Member] \| Performing Financing Receivable [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Finance receivable recorded investment, Performing	147,383	153,113
Consumer - Other [Member] \| Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Finance receivable recorded investment, Nonperforming	$ 2,456	$ 1,599

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- Definition

Amount of financing receivable not past due.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 20
-Section 55
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-Publisher FASB
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+ References

No definition available.

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Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
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