Condensed Parent Company Only Financial Statements - Condensed Cash Flow Statements (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating activities
Net income	$ 89,264	$ 77,588	$ 81,718
Adjustments to reconcile net income to net cash provided by operating activities
Other, net	(11,223)	6,218	(8,113)
Net Cash Provided by Operating Activities	121,177	101,387	101,615
Investing activities
Other, net	23	489	5,209
Net Cash (Used in) Provided by Investing Activities	(583,294)	(643,719)	133,986
Financing activities
Cash dividends	(32,415)	(31,359)	(30,637)
Repurchase of common shares	(23,773)	(9,414)	(29,867)
Redemption of trust preferred debentures	(15,150)	(4,124)	0
Net proceeds from restricted stock awards	(2,292)	(1,682)	(1,875)
Shares issued for dividend reinvestment plan	2	1,825	0
Net proceeds from exercise of stock options	(803)	(253)	(992)
Net Cash Provided by (Used in) Financing Activities	136,762	792,812	(178,008)
Net (Decrease) Increase Cash and Cash Equivalents	(325,355)	250,480	57,593
Cash and cash equivalents at beginning of year	388,462	137,982	80,389
Total Cash & Cash Equivalents at End of Year	63,107	388,462	137,982
Tompkins (the Parent Company)
Operating activities
Net income	89,264	77,588	81,718
Adjustments to reconcile net income to net cash provided by operating activities
Equity in undistributed earnings of subsidiaries	(16,780)	(24,983)	(16,425)
Other, net	4,126	(1,541)	3,209
Net Cash Provided by Operating Activities	76,610	51,064	68,502
Investing activities
Other, net	(76)	(100)	3,265
Net Cash (Used in) Provided by Investing Activities	(76)	(100)	3,265
Financing activities
Borrowings, net	0	(4,000)	0
Cash dividends	(32,415)	(31,359)	(30,637)
Repurchase of common shares	(23,773)	(9,414)	(29,867)
Redemption of trust preferred debentures	(15,150)	(4,124)	0
Net proceeds from restricted stock awards	(2,292)	(1,682)	(1,875)
Shares issued for dividend reinvestment plan	2	1,825	0
Shares issued for employee stock ownership plan	0	0	0
Net proceeds from exercise of stock options	(803)	(253)	(992)
Net Cash Provided by (Used in) Financing Activities	(74,431)	(49,007)	(63,371)
Net (Decrease) Increase Cash and Cash Equivalents	2,103	1,957	8,396
Cash and cash equivalents at beginning of year	16,588	14,631	6,235
Total Cash & Cash Equivalents at End of Year	$ 18,691	$ 16,588	$ 14,631