Business Combination and Asset Purchase - Additional Information (Detail)						3 Months Ended	9 Months Ended
	Oct. 01, 2022 USD ($) Office $ / shares shares	Oct. 01, 2021 USD ($) Office $ / shares shares	Apr. 30, 2021 USD ($) Office $ / shares shares	Nov. 16, 2020 USD ($) shares	Jan. 01, 2019 USD ($) shares $ / shares	Sep. 30, 2023 USD ($) shares	Sep. 30, 2023 USD ($) shares	Sep. 30, 2022 USD ($)	Dec. 31, 2022 USD ($) shares	Nov. 30, 2020 USD ($) Client
Business Acquisition [Line Items]
Common stock, shares outstanding | shares						14,564,425	14,564,425		14,564,425
Goodwill						$ 86,358,000	$ 86,358,000		$ 86,358,000
Pro-forma operating revenue, net of tax						316,000	1,000,000
Amortization expense							1,242,000	$ 597,000
Core Deposits [Member]
Business Acquisition [Line Items]
Amortization expense							1,200,000	597,000
Amortization expense for 2023						1,656,000	1,656,000
Customer Lists [Member]
Business Acquisition [Line Items]
Amortization expense							92,000	$ 92,000
Amortization expense for 2023						123,000	123,000
Peoples Federal Savings and Loan [Member]
Business Acquisition [Line Items]
Number of full-service offices | Office	3
Common stock issued in exchange of each outstanding share	0.6597
Cash payment for exchange of each share | $ / shares	$ 24
Minimum number of shares to be exchanged under merger agreement | shares	758,566
Common stock, shares outstanding | shares	1,167,025
Share price | $ / shares	$ 26.87
Total consideration for acquisition	$ 23,249,000
Cash paid for the capital stock	9,806,000
Stock issued for acquisition	13,446,000
Goodwill	5,924,000
Fair value of assets acquired	101,800,000
Gross principal and contractual interest	116,100,000
Acquisition expected to be uncollectible	$ 0
Loan receivable weighted average life	44 months 12 days
Business combination, premises and equipment written up value	$ 581,000
Business combination, premises and equipment written down value	$ 597,000
Business combination, average remaining life	12 years 9 months 18 days
Fair value for certificate of deposit, valuation amount	$ 662,000
Fair value for certificate of deposit, amortization period	1 year 1 month 6 days
Fair value of Federal Home Loan Bank (FHLB) advances, valuation amount	$ 69,000
Fair value of Federal Home Loan Bank (FHLB) advances, amortization period	5 years 2 months 12 days
Peoples Federal Savings and Loan [Member] | Core Deposits [Member]
Business Acquisition [Line Items]
Recognition of core deposit intangible asset with acquired purchase	$ 6,000,000
Remaining economic useful life	7 years
Recognition of core deposit tangible asset with acquired purchase							6,000,000
Amortization expense for 2023						861,000	861,000
Perpetual Federal Savings Bank [Member]
Business Acquisition [Line Items]
Number of full-service offices | Office		1
Common stock issued in exchange of each outstanding share		1.7766
Cash payment for exchange of each share | $ / shares		$ 41.20
Business acquisition share owned subject to adjustment | shares		1,833,999
Common stock, shares outstanding | shares		2,470,032
Share price | $ / shares		$ 22.4
Total consideration for acquisition		$ 100,312,000
Cash paid for the capital stock		59,234,000
Stock issued for acquisition		41,078,000
Goodwill		25,220,000
Fair value of assets acquired		334,700,000
Gross principal and contractual interest		403,300,000
Acquisition expected to be uncollectible		$ 5,600,000
Loan receivable weighted average life		52 months
Business combination, premises and equipment written down value		$ 4,000
Business combination, average remaining life		16 years 2 months 12 days
Fair value for certificate of deposit, valuation amount		$ 3,900,000
Fair value for certificate of deposit, amortization period		1 year 7 months 6 days
Fair value of Federal Home Loan Bank (FHLB) advances, valuation amount		$ 218,000
Fair value of Federal Home Loan Bank (FHLB) advances, amortization period		2 years 7 months 6 days
Perpetual Federal Savings Bank [Member] | Building [Member]
Business Acquisition [Line Items]
Business combination, premises and equipment written down value		$ 297,000
Perpetual Federal Savings Bank [Member] | Core Deposits [Member]
Business Acquisition [Line Items]
Recognition of core deposit intangible asset with acquired purchase		$ 668,000
Remaining economic useful life		7 years
Amortization expense for 2023						95,000	95,000
Ossian State Bank [Member]
Business Acquisition [Line Items]
Number of full-service offices | Office			2
Ossian State Bank [Member] | Core Deposits [Member]
Business Acquisition [Line Items]
Recognition of core deposit tangible asset with acquired purchase							980,200
Ossian Financial Services, Inc. [Member]
Business Acquisition [Line Items]
Cash payment for exchange of each share | $ / shares			$ 67.71
Common stock, shares outstanding | shares			295,388
Total consideration for acquisition			$ 20,001,000
Cash paid for the capital stock			20,001,000
Goodwill			7,874,000
Fair value of assets acquired			52,400,000
Gross principal and contractual interest			63,700,000
Acquisition expected to be uncollectible			$ 1,100,000
Loan receivable weighted average life			52 months
Business combination, premises and equipment written down value			$ 596,000
Business combination, average remaining life			39 years
Fair value for certificate of deposit, valuation amount			$ 59,000
Fair value for certificate of deposit, amortization period			1 year 4 months 24 days
Goodwill deductible for tax purpose, period			15 years
Ossian Financial Services, Inc. [Member] | Building [Member]
Business Acquisition [Line Items]
Business combination, premises and equipment written down value			$ 244,000
Ossian Financial Services, Inc. [Member] | Core Deposits [Member]
Business Acquisition [Line Items]
Recognition of core deposit intangible asset with acquired purchase			$ 980,200
Remaining economic useful life			7 years
Amortization expense for 2023						$ 140,000	140,000
Bank of Geneva [Member] | Core Deposits [Member]
Business Acquisition [Line Items]
Recognition of core deposit intangible asset with acquired purchase							$ 3,900,000
Remaining economic useful life						7 years	7 years
Limberlost Bancshares, Inc. [Member]
Business Acquisition [Line Items]
Common stock issued in exchange of each outstanding share | shares					1,830
Cash payment for exchange of each share | $ / shares					$ 8,465
Common stock, shares outstanding | shares					1,000
Share price | $ / shares					$ 38.49
Total consideration for acquisition					$ 78,900,000
Cash paid for the capital stock					8,500,000
Stock issued for acquisition					70,400,000
Goodwill					43,300,000
Limberlost Bancshares, Inc. [Member] | Core Deposits [Member]
Business Acquisition [Line Items]
Recognition of core deposit intangible asset with acquired purchase					$ 3,900,000
Remaining economic useful life					7 years
Perpetual Federal Savings Bank [Member] | Core Deposits [Member]
Business Acquisition [Line Items]
Recognition of core deposit tangible asset with acquired purchase							$ 668,000
Adams County Financial Resources [Member]
Business Acquisition [Line Items]
Total consideration for acquisition				$ 825,000
Common stock issued in exchange of each outstanding share | shares				40,049
Assets under management amount										$ 83,000,000
Number of clients assets under management | Client										450
Adams County Financial Resources [Member] | Customer Lists [Member]
Business Acquisition [Line Items]
Recognition of core deposit intangible asset with acquired purchase				$ 800,000
Remaining economic useful life				6 years 6 months
Amortization expense for 2023						$ 123,000	$ 123,000