Segment and Related Information - Schedule of Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Interest income	$ 63,199	$ 64,928
Interest expense	10,230	13,014
Net Interest Income	52,969	51,914
Provision for credit loss expense	16,294	445
Noninterest income	18,960	19,407
Noninterest expense	45,740	44,209
Income Before Income Tax Expense	9,895	26,667
Income tax expense	1,909	5,595
Net Income Attributable to Noncontrolling Interests and Tompkins Financial Corporation	7,986	21,072
Less: Net Income Attributable to Noncontrolling Interests	37	32
Net Income Attributable to Tompkins Financial Corporation	7,949	21,040
Depreciation and amortization	2,554	2,480
Assets	6,743,114	6,738,719	$ 6,725,623
Goodwill	92,447	92,283	92,447
Other intangibles, net	5,847	7,266	6,223
Net loans and leases	4,885,418	4,749,372	4,877,658
Deposits	5,409,363	4,989,925	5,212,921
Total Equity	682,597	647,267	$ 663,054	$ 620,871
Operating Segments | Banking
Segment Reporting Information [Line Items]
Interest income	63,199	64,929
Interest expense	10,231	13,016
Net Interest Income	52,968	51,913
Provision for credit loss expense	16,294	445
Noninterest income	6,992	7,568
Noninterest expense	36,689	35,327
Income Before Income Tax Expense	6,977	23,709
Income tax expense	1,157	4,834
Net Income Attributable to Noncontrolling Interests and Tompkins Financial Corporation	5,820	18,875
Less: Net Income Attributable to Noncontrolling Interests	37	32
Net Income Attributable to Tompkins Financial Corporation	5,783	18,843
Depreciation and amortization	2,485	2,414
Assets	6,690,574	6,689,882
Goodwill	64,585	64,370
Other intangibles, net	2,972	4,019
Net loans and leases	4,885,418	4,749,372
Deposits	5,422,258	5,003,696
Total Equity	627,223	593,791
Operating Segments | Insurance
Segment Reporting Information [Line Items]
Interest income	1	1
Interest expense	0	0
Net Interest Income	1	1
Provision for credit loss expense	0	0
Noninterest income	8,150	8,148
Noninterest expense	6,562	6,277
Income Before Income Tax Expense	1,589	1,872
Income tax expense	430	490
Net Income Attributable to Noncontrolling Interests and Tompkins Financial Corporation	1,159	1,382
Less: Net Income Attributable to Noncontrolling Interests	0	0
Net Income Attributable to Tompkins Financial Corporation	1,159	1,382
Depreciation and amortization	59	56
Assets	41,444	41,156
Goodwill	19,866	19,702
Other intangibles, net	2,741	3,051
Net loans and leases	0	0
Deposits	0	0
Total Equity	32,632	33,774
Operating Segments | Wealth Management
Segment Reporting Information [Line Items]
Interest income	0	0
Interest expense	0	0
Net Interest Income	0	0
Provision for credit loss expense	0	0
Noninterest income	4,374	4,198
Noninterest expense	3,045	3,112
Income Before Income Tax Expense	1,329	1,086
Income tax expense	322	271
Net Income Attributable to Noncontrolling Interests and Tompkins Financial Corporation	1,007	815
Less: Net Income Attributable to Noncontrolling Interests	0	0
Net Income Attributable to Tompkins Financial Corporation	1,007	815
Depreciation and amortization	10	10
Assets	24,562	21,573
Goodwill	7,996	8,211
Other intangibles, net	134	196
Net loans and leases	0	0
Deposits	0	0
Total Equity	22,742	19,702
Intercompany
Segment Reporting Information [Line Items]
Interest income	(1)	(2)
Interest expense	(1)	(2)
Net Interest Income	0	0
Provision for credit loss expense	0	0
Noninterest income	(556)	(507)
Noninterest expense	(556)	(507)
Income Before Income Tax Expense	0	0
Income tax expense	0	0
Net Income Attributable to Noncontrolling Interests and Tompkins Financial Corporation	0	0
Less: Net Income Attributable to Noncontrolling Interests	0	0
Net Income Attributable to Tompkins Financial Corporation	0	0
Depreciation and amortization	0	0
Assets	(13,466)	(13,892)
Goodwill	0	0
Other intangibles, net	0	0
Net loans and leases	0	0
Deposits	(12,895)	(13,771)
Total Equity	$ 0	$ 0