Other Comprehensive Income (Loss) - Schedule of Amounts Reclassified Out of Each Component (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2023
Jun. 30, 2022
Jun. 30, 2023
Jun. 30, 2022
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]        
Net (loss) gain on securities transactions $ (7,065) $ (37) $ (7,052) $ (84)
Tax (expense) benefit (1,784) (6,329) (7,685) (13,305)
Other operating expense (14,468) (13,029) (27,937) (25,049)
Total before tax 10,290 27,230 35,603 57,510
Net income attributable to Tompkins Financial Corporation 8,475 20,869 27,856 44,142
Amount Reclassified from Accumulated Other Comprehensive (Loss) Income | Available-for-sale securities        
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]        
Net (loss) gain on securities transactions (7,052) 0 (7,052)  
Tax (expense) benefit 1,727 0 1,727 0
Total before tax       0
Net income attributable to Tompkins Financial Corporation (5,325) 0 (5,325) 0
Amount Reclassified from Accumulated Other Comprehensive (Loss) Income | Net retirement plan actuarial loss        
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]        
Other operating expense (261) (514) (558) (1,129)
Amount Reclassified from Accumulated Other Comprehensive (Loss) Income | Net retirement plan prior service cost        
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]        
Other operating expense (54) (53) (109) (109)
Amount Reclassified from Accumulated Other Comprehensive (Loss) Income | Employee benefit plans        
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]        
Tax (expense) benefit 77 138 164 303
Total before tax (315) (567) (667) (1,238)
Net income attributable to Tompkins Financial Corporation $ (238) $ (429) $ (503) $ (935)