Loans - Summary of Nonaccrual Loans Segregated by Class of Loan (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2026	Dec. 31, 2025
Nonaccrual loans, Segregated by class of loans [Abstract]
Nonaccrual status loans	$ 38,160	$ 27,561
Nonaccrual loans without related allowance for credit loss	14,976	4,853
Recognized interest income	69	1,158
Residential Mortgage Loans [Member]
Nonaccrual loans, Segregated by class of loans [Abstract]
Nonaccrual status loans	2,213	1,977
Nonaccrual loans without related allowance for credit loss	0	0
Recognized interest income	17	108
Residential Mortgage Loans [Member] \| Residential 1-4 Family First Mortgages [Member]
Nonaccrual loans, Segregated by class of loans [Abstract]
Nonaccrual status loans	2,213	1,977
Nonaccrual loans without related allowance for credit loss	0	0
Recognized interest income	17	108
Commercial Loans [Member]
Nonaccrual loans, Segregated by class of loans [Abstract]
Nonaccrual status loans	34,831	24,616
Nonaccrual loans without related allowance for credit loss	14,976	4,853
Recognized interest income	33	986
Commercial Loans [Member] \| Real Estate [Member]
Nonaccrual loans, Segregated by class of loans [Abstract]
Nonaccrual status loans	24,929	15,567
Nonaccrual loans without related allowance for credit loss	14,038	4,853
Recognized interest income	11	428
Commercial Loans [Member] \| Lines of Credit [Member]
Nonaccrual loans, Segregated by class of loans [Abstract]
Nonaccrual status loans	1,895	1,135
Nonaccrual loans without related allowance for credit loss	749	0
Recognized interest income	1	109
Commercial Loans [Member] \| Other Commercial and Industrial [Member]
Nonaccrual loans, Segregated by class of loans [Abstract]
Nonaccrual status loans	8,007	7,914
Nonaccrual loans without related allowance for credit loss	189	0
Recognized interest income	21	449
Consumer Loans [Member]
Nonaccrual loans, Segregated by class of loans [Abstract]
Nonaccrual status loans	1,116	968
Nonaccrual loans without related allowance for credit loss	0	0
Recognized interest income	19	64
Consumer Loans [Member] \| Home Equity and Junior Liens [Member]
Nonaccrual loans, Segregated by class of loans [Abstract]
Nonaccrual status loans	647	537
Nonaccrual loans without related allowance for credit loss	0	0
Recognized interest income	9	44
Consumer Loans [Member] \| Other Consumer [Member]
Nonaccrual loans, Segregated by class of loans [Abstract]
Nonaccrual status loans	469	431
Nonaccrual loans without related allowance for credit loss	0	0
Recognized interest income	$ 10	$ 20

Pathfinder Bancorp, Inc. 10-Q