Securities - Schedule of Available-for-Sale Securities with Unrealized Losses (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Dec. 31, 2024
Fair Value
Fair Value, Less than 12 Months	$ 45,932	$ 76,389
Fair Value, 12 Months or Longer	789,496	880,651
Fair Value	835,428	957,040
Unrealized Losses
Unrealized Losses, Less than 12 Months	286	1,142
Unrealized Losses, 12 Months or Longer	101,782	138,284
Unrealized Losses	102,068	139,426
U.S. Treasuries
Fair Value
Fair Value, Less than 12 Months	0	0
Fair Value, 12 Months or Longer	38,655	57,019
Fair Value	38,655	57,019
Unrealized Losses
Unrealized Losses, Less than 12 Months	0	0
Unrealized Losses, 12 Months or Longer	2,194	3,784
Unrealized Losses	2,194	3,784
Obligations of U.S. Government sponsored entities
Fair Value
Fair Value, Less than 12 Months	0	14,085
Fair Value, 12 Months or Longer	150,482	188,296
Fair Value	150,482	202,381
Unrealized Losses
Unrealized Losses, Less than 12 Months	0	515
Unrealized Losses, 12 Months or Longer	12,753	19,861
Unrealized Losses	12,753	20,376
Obligations of U.S. states and political subdivisions
Fair Value
Fair Value, Less than 12 Months	2,533	3,159
Fair Value, 12 Months or Longer	64,883	73,657
Fair Value	67,416	76,816
Unrealized Losses
Unrealized Losses, Less than 12 Months	1	36
Unrealized Losses, 12 Months or Longer	5,631	8,602
Unrealized Losses	5,632	8,638
U.S. Government agencies
Fair Value
Fair Value, Less than 12 Months	13,501	27,082
Fair Value, 12 Months or Longer	40,746	35,879
Fair Value	54,247	62,961
Unrealized Losses
Unrealized Losses, Less than 12 Months	19	89
Unrealized Losses, 12 Months or Longer	3,683	4,790
Unrealized Losses	3,702	4,879
U.S. Government sponsored entities
Fair Value
Fair Value, Less than 12 Months	29,898	32,063
Fair Value, 12 Months or Longer	492,286	523,353
Fair Value	522,184	555,416
Unrealized Losses
Unrealized Losses, Less than 12 Months	266	502
Unrealized Losses, 12 Months or Longer	77,465	101,194
Unrealized Losses	77,731	101,696
U.S. corporate debt securities
Fair Value
Fair Value, Less than 12 Months	0	0
Fair Value, 12 Months or Longer	2,444	2,447
Fair Value	2,444	2,447
Unrealized Losses
Unrealized Losses, Less than 12 Months	0	0
Unrealized Losses, 12 Months or Longer	56	53
Unrealized Losses	$ 56	$ 53

TOMPKINS FINANCIAL CORP 10-Q