CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Additional Paid-in Capital	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive (Loss) Income	Treasury Stock	Non- controlling Interests
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of new accounting principle	$ 663,054	$ 1,707	$ 1,501	$ 338,507	$ 370,477	$ 1,707	$ (43,564)	$ (5,279)	$ 1,412
Balances at Beginning 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]
Cumulative effect of new accounting principle	682,597	$ 1,707	1,494	333,662	372,344	$ 1,707	(43,564)	(5,076)	1,444
Net income attributable to noncontrolling interests and Tompkins Financial Corporation	7,986				7,949				37
Other comprehensive (loss) income	22,293						22,293
Total Comprehensive Income	30,279
Cash dividends	(7,789)				(7,789)
Net exercise of stock options	(209)			(209)
Common stock repurchased and returned to unissued status	(5,620)		(7)	(5,613)
Stock-based compensation expense	1,180			1,180
Directors deferred compensation plan	0			(203)				203
Restricted stock activity	0
Partial repurchase of noncontrolling interest	(5)								(5)
Balances at Ending at Mar. 31, 2020	682,597		1,494	333,662	372,344		(21,271)	(5,076)	1,444
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of new accounting principle	682,597		1,494	333,662	372,344		(21,271)	(5,076)	1,444
Cumulative effect of new accounting principle	717,689		1,496	333,976	418,413		(32,074)	(5,534)	1,412
Balances at Beginning at Dec. 31, 2020	717,689		1,496	333,976	418,413		(32,074)	(5,534)	1,412
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of new accounting principle	717,689		1,494	333,247	435,990		(56,950)	(5,288)	1,443
Net income attributable to noncontrolling interests and Tompkins Financial Corporation	25,659				25,626				33
Other comprehensive (loss) income	(24,876)						(24,876)
Total Comprehensive Income	783
Cash dividends	(8,049)				(8,049)
Net exercise of stock options	(152)			(152)
Common stock repurchased and returned to unissued status	(1,508)		(2)	(1,506)
Stock-based compensation expense	1,175			1,175
Directors deferred compensation plan	0			(246)				246
Restricted stock activity	0
Partial repurchase of noncontrolling interest	(2)								(2)
Balances at Ending at Mar. 31, 2021	709,936		1,494	333,247	435,990		(56,950)	(5,288)	1,443
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of new accounting principle	$ 709,936		$ 1,494	$ 333,247	$ 435,990		$ (56,950)	$ (5,288)	$ 1,443