Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Consolidated Statements of Comprehensive Income [Abstract]
Net (loss) income	$ (4,616)	$ 2,194	$ (431)	$ 6,844
Retirement Plans:
Retirement plan net gains recognized in plan expenses	38	56	113	167
Net unrealized gain on retirement plans	38	56	113	167
Unrealized holding gains (losses) on available-for-sale securities:
Unrealized holding gains (losses) arising during the period	2,847	(3,016)	3,085	(4,093)
Reclassification adjustment for net (gains) losses included in net income	0	(1)	139	1,932
Net unrealized gains (losses) on available-for-sale securities	2,847	(3,017)	3,224	(2,161)
Derivatives and hedging activities:
Unrealized holding (losses) gains arising during the period	(82)	273	574	391
Net unrealized (losses) gains on derivatives and hedging activities	(82)	273	574	391
Other comprehensive income (loss), before tax	2,803	(2,688)	3,911	(1,603)
Tax effect	(733)	702	(1,022)	419
Other comprehensive income (loss), net of tax	2,070	(1,986)	2,889	(1,184)
Comprehensive (loss) income	(2,546)	208	2,458	5,660
Comprehensive income attributable to noncontrolling interest	28	18	93	87
Comprehensive (loss) income attributable to Pathfinder Bancorp, Inc.	(2,574)	190	2,365	5,573
Tax Effect Allocated to Each Component of Other Comprehensive (Loss) Income
Retirement plan net gains recognized in plan expenses	(10)	(15)	(30)	(44)
Unrealized holding (gains) losses on available-for-sale securities arising during the period	(744)	788	(806)	1,070
Reclassification adjustment for net losses on available-for-sale securities included in net income	0	0	(36)	(506)
Unrealized (gains) losses on derivatives and hedging arising during the period	21	(71)	(150)	(101)
Income tax effect related to other comprehensive (loss) income	$ (733)	$ 702	$ (1,022)	$ 419