CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Cumulative Effect, Adjustment	Common Stock	Additional Paid-in Capital	Retained Earnings	Retained Earnings Cumulative Effect, Adjustment	Accumulated Other Comprehensive (Loss) Income	Accumulated Other Comprehensive (Loss) Income Cumulative Effect, Adjustment	Treasury Stock	Non- controlling Interests
Balances at beginning at Dec. 31, 2017	$ 576,202		$ 1,530	$ 364,031	$ 265,007		$ (51,296)		$ (4,492)	$ 1,422
Balances at beginning (Adoption of Accounting Guidance ASU 2016-01) at Dec. 31, 2017		$ 0				$ (65)		$ 65
Balances at beginning (Adoption of Accounting Guidance ASU 2014-09) at Dec. 31, 2017		1,780				1,780
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to noncontrolling interests and Tompkins Financial Corporation	82,435				82,308					127
Other comprehensive income (loss)	(11,934)						(11,934)
Subtotal comprehensive income attributable to noncontrolling interests and Tompkins Financial Corporation	70,501
Cash dividends	(29,634)				(29,634)
Net exercise of stock options	(540)		1	(541)
Common stock repurchased and returned to unissued status	(2,448)		(3)	(2,445)
Stock-based compensation expense	3,477			3,477
Shares issued for employee stock ownership plan	3,073		4	3,069
Directors deferred compensation plan	0			410					(410)
Restricted stock activity	(1,403)		3	(1,406)
Partial repurchase of noncontrolling interest	(10)									(10)
Dividend to noncontrolling interests	(127)									(127)
Balances at ending at Dec. 31, 2018	620,871		1,535	366,595	319,396		(63,165)		(4,902)	1,412
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to noncontrolling interests and Tompkins Financial Corporation	81,845				81,718					127
Other comprehensive income (loss)	19,601						19,601
Subtotal comprehensive income attributable to noncontrolling interests and Tompkins Financial Corporation	101,446
Cash dividends	(30,637)				(30,637)
Net exercise of stock options	(992)		2	(994)
Common stock repurchased and returned to unissued status	(29,867)		(38)	(29,829)
Stock-based compensation expense	4,235			4,235
Directors deferred compensation plan	0			377					(377)
Restricted stock activity	$ (1,875)		2	(1,877)
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member
Dividend to noncontrolling interests	$ (127)									(127)
Balances at ending at Dec. 31, 2019	663,054	$ 1,707	1,501	338,507	370,477	$ 1,707	(43,564)		(5,279)	1,412
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to noncontrolling interests and Tompkins Financial Corporation	77,742				77,588					154
Other comprehensive income (loss)	11,490						11,490
Subtotal comprehensive income attributable to noncontrolling interests and Tompkins Financial Corporation	89,232
Cash dividends	(31,359)				(31,359)
Net exercise of stock options	(253)		1	(254)
Common stock repurchased and returned to unissued status	(9,414)		(13)	(9,401)
Stock-based compensation expense	4,733			4,733
Shares issued for dividend reinvestment plan	1,825		3	1,822
Directors deferred compensation plan	0			255					(255)
Restricted stock activity	(1,682)		4	(1,686)
Partial repurchase of noncontrolling interest	(6)									(6)
Dividend to noncontrolling interests	(148)									(148)
Balances at ending at Dec. 31, 2020	$ 717,689		$ 1,496	$ 333,976	$ 418,413		$ (32,074)		$ (5,534)	$ 1,412