Condensed Parent Company Only Financial Statements - Condensed Statement of Income (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Condensed Income Statements, Captions [Line Items]
Interest expense	$ 12,089	$ 10,821	$ 9,429	$ 7,453	$ 7,060	$ 6,772	$ 6,041	$ 5,587	$ 39,792	$ 25,460	$ 22,103
Net (loss) gain on securities transactions	23,808	26,361	27,842	26,229	20,981	25,917	25,207	23,137	104,240	95,242	86,516
Income tax benefit									(21,805)	(42,620)	(27,045)
Net Income Attributable to Tompkins Financial Corporation	$ 18,911	$ 20,902	$ 22,059	$ 20,436	$ 2,457	$ 17,394	$ 16,926	$ 15,717	82,308	52,494	59,340
Tompkins (the Parent Company)
Condensed Income Statements, Captions [Line Items]
Dividends received from subsidiaries									44,518	33,522	47,584
Other income									332	281	269
Total Operating Income									44,850	33,803	47,853
Interest expense									1,468	1,550	2,743
Other expenses									7,222	6,120	6,089
Total Operating Expenses									8,690	7,670	8,832
Net (loss) gain on securities transactions									36,160	26,133	39,021
Income tax benefit									1,687	1,867	3,549
Equity in undistributed earnings of subsidiaries									44,461	24,494	16,770
Net Income Attributable to Tompkins Financial Corporation									$ 82,308	$ 52,494	$ 59,340