Business Combination & Asset Purchase - Additional Information (Detail)					12 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 ($) shares	Dec. 31, 2023 USD ($) shares	Dec. 31, 2022 USD ($) shares	Dec. 31, 2021 USD ($)	Nov. 30, 2020 USD ($) Client
Business Acquisition [Line Items]
Common stock, shares outstanding | shares					14,564,425	14,564,425
Goodwill					$ 86,358,000	$ 86,358,000
Amortization expense					1,657,000	1,011,000	$ 677,000
Customer Lists [Member]
Business Acquisition [Line Items]
Amortization expense					123,000	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					9,806,000
Stock issued for acquisition	13,446,000
Business combination, acquisition related costs					200,000	2,400,000
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, 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] | Building [Member]
Business Acquisition [Line Items]
Business combination, premises and equipment written up value	$ 597,000
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				6,000,000
Remaining economic useful life	7 years
Peoples Federal Savings and Loan [Member] | Data Processing [Member]
Business Acquisition [Line Items]
Business combination, acquisition related costs					12,900	1,100,000
Peoples Federal Savings and Loan [Member] | Consulting Fees [Member]
Business Acquisition [Line Items]
Business combination, acquisition related costs					5,200	542,900
Peoples Federal Savings and Loan [Member] | Employee Benefits [Member]
Business Acquisition [Line Items]
Business combination, acquisition related costs					137,200	126,500
Peoples Federal Savings and Loan [Member] | Other General and Administrative Expenses [Member]
Business Acquisition [Line Items]
Business combination, acquisition related costs					44,700	501,000
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		$ 22.40
Total consideration for acquisition		$ 100,312,000
Cash paid for the capital stock		59,234,000					59,234,000
Stock issued for acquisition		41,078,000
Business combination, acquisition related costs						148,500,000	1,700,000
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
Common stock issued in exchange of each outstanding share | shares	500,426	1,833,845
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			668,000
Remaining economic useful life		7 years
Perpetual Federal Savings Bank [Member] | Data Processing [Member]
Business Acquisition [Line Items]
Business combination, acquisition related costs							444,900
Perpetual Federal Savings Bank [Member] | Consulting Fees [Member]
Business Acquisition [Line Items]
Business combination, acquisition related costs							636,800
Perpetual Federal Savings Bank [Member] | Employee Benefits [Member]
Business Acquisition [Line Items]
Business combination, acquisition related costs						90,800	131,500
Perpetual Federal Savings Bank [Member] | Other General and Administrative Expenses [Member]
Business Acquisition [Line Items]
Business combination, acquisition related costs						57,700	488,300
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 intangible 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
Business combination, acquisition related costs						$ 31,600	2,200,000
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
Ossian Financial Services, Inc. [Member] | Data Processing [Member]
Business Acquisition [Line Items]
Business combination, acquisition related costs							938,900
Ossian Financial Services, Inc. [Member] | Consulting Fees [Member]
Business Acquisition [Line Items]
Business combination, acquisition related costs							255,200
Ossian Financial Services, Inc. [Member] | Employee Benefits [Member]
Business Acquisition [Line Items]
Business combination, acquisition related costs							694,100
Ossian Financial Services, Inc. [Member] | ATM Expense [Member]
Business Acquisition [Line Items]
Business combination, acquisition related costs							13,800
Ossian Financial Services, Inc. [Member] | Other General and Administrative Expenses [Member]
Business Acquisition [Line Items]
Business combination, acquisition related costs							$ 255,000.0
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
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