Condensed Parent Company Only Financial Statements - Condensed Statement of Income (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Condensed Income Statements, Captions [Line Items]
Dividends from available-for-sale securities									$ 29,721	$ 27,846	$ 29,525
Interest expense	$ 7,060	$ 6,772	$ 6,041	$ 5,587	$ 5,562	$ 5,760	$ 5,510	$ 5,271	25,460	22,103	20,365
Net (loss) gain on securities transactions	20,981	25,917	25,207	23,137	21,595	22,116	21,625	21,180	95,242	86,516	87,514
Income tax benefit									(42,620)	(27,045)	(28,962)
Net Income attributable to Tompkins Financial Corporation	$ 2,457	$ 17,394	$ 16,926	$ 15,717	$ 15,118	$ 15,138	$ 14,833	$ 14,251	52,494	59,340	58,421
Tompkins (the Parent Company)
Condensed Income Statements, Captions [Line Items]
Dividends from available-for-sale securities									0	0	2
Dividends received from subsidiaries									33,522	47,584	28,667
Other income									281	269	593
Total Operating Income									33,803	47,853	29,262
Interest expense									1,550	2,743	2,648
Other expenses									6,120	6,089	5,996
Total Operating Expenses									7,670	8,832	8,644
Net (loss) gain on securities transactions									26,133	39,021	20,618
Income tax benefit									1,867	3,549	2,987
Equity in undistributed earnings of subsidiaries									24,494	16,770	34,816
Net Income attributable to Tompkins Financial Corporation									$ 52,494	$ 59,340	$ 58,421