Investment and Equity Securities - Gross Unrealized Losses and Fair Value of Investments (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Gross unrealized losses, Less than Twelve Months, Fair Value	$ 249,291	$ 197,371
Available-for-sale Securities, Gross unrealized losses, Less than Twelve Months, Unrealized Losses	17,286	3,320
Available-for-sale Securities, Gross unrealized losses, Twelve Months or More, Fair Value	36,931	15,795
Available-for-sale Securities, Gross unrealized losses, Twelve Months or More, Unrealized Losses	2,885	468
Available-for-sale Securities, Gross unrealized losses, Fair Value	286,222	213,166
Available-for-sale Securities, Gross unrealized losses, Unrealized Losses	20,171	3,788
U.S. Treasury [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Gross unrealized losses, Less than Twelve Months, Fair Value	31,410	16,306
Available-for-sale Securities, Gross unrealized losses, Less than Twelve Months, Unrealized Losses	2,021	310
Available-for-sale Securities, Gross unrealized losses, Fair Value	31,410	16,306
Available-for-sale Securities, Gross unrealized losses, Unrealized Losses	2,021	310
U.S. Government Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Gross unrealized losses, Less than Twelve Months, Fair Value	14,335	19,702
Available-for-sale Securities, Gross unrealized losses, Less than Twelve Months, Unrealized Losses	383	396
Available-for-sale Securities, Gross unrealized losses, Twelve Months or More, Fair Value	10,944	2,313
Available-for-sale Securities, Gross unrealized losses, Twelve Months or More, Unrealized Losses	302	30
Available-for-sale Securities, Gross unrealized losses, Fair Value	25,279	22,015
Available-for-sale Securities, Gross unrealized losses, Unrealized Losses	685	426
GSE - Mortgage-backed Securities and CMO’s [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Gross unrealized losses, Less than Twelve Months, Fair Value	105,231	93,928
Available-for-sale Securities, Gross unrealized losses, Less than Twelve Months, Unrealized Losses	7,084	1,607
Available-for-sale Securities, Gross unrealized losses, Twelve Months or More, Fair Value	12,421	4,210
Available-for-sale Securities, Gross unrealized losses, Twelve Months or More, Unrealized Losses	594	129
Available-for-sale Securities, Gross unrealized losses, Fair Value	117,652	98,138
Available-for-sale Securities, Gross unrealized losses, Unrealized Losses	7,678	1,736
Asset-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Gross unrealized losses, Less than Twelve Months, Fair Value	19,525	8,531
Available-for-sale Securities, Gross unrealized losses, Less than Twelve Months, Unrealized Losses	218	60
Available-for-sale Securities, Gross unrealized losses, Fair Value	19,525	8,531
Available-for-sale Securities, Gross unrealized losses, Unrealized Losses	218	60
State and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Gross unrealized losses, Less than Twelve Months, Fair Value	72,790	52,959
Available-for-sale Securities, Gross unrealized losses, Less than Twelve Months, Unrealized Losses	7,371	892
Available-for-sale Securities, Gross unrealized losses, Twelve Months or More, Fair Value	13,566	9,272
Available-for-sale Securities, Gross unrealized losses, Twelve Months or More, Unrealized Losses	1,989	309
Available-for-sale Securities, Gross unrealized losses, Fair Value	86,356	62,231
Available-for-sale Securities, Gross unrealized losses, Unrealized Losses	9,360	1,201
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Gross unrealized losses, Less than Twelve Months, Fair Value	6,000	5,945
Available-for-sale Securities, Gross unrealized losses, Less than Twelve Months, Unrealized Losses	209	55
Available-for-sale Securities, Gross unrealized losses, Fair Value	6,000	5,945
Available-for-sale Securities, Gross unrealized losses, Unrealized Losses	$ 209	$ 55

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=124269663&loc=SL82922890-210455

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27337-111563

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=121590138&loc=SL82922954-210456

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for 12 months or longer, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

+ References

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for less than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27337-111563

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=124269663&loc=SL82922890-210455

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=121590138&loc=SL82922954-210456

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for less than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

+ References

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position without allowance for credit loss.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27290-111563

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 50
-Paragraph 4
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=124269663&loc=SL82922888-210455

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=121590138&loc=SL82922954-210456

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

+ References

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- 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

Name:	us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_USTreasurySecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_USGovernmentAgenciesDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_MortgageBackedSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_AssetBackedSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_USStatesAndPoliticalSubdivisionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InvestmentTypeAxis=us-gaap_CorporateBondSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: