Segment and Related Information - Narrative (Details)	12 Months Ended
	Dec. 31, 2022 segment	Dec. 31, 2022 banking_Office	Dec. 31, 2022 subsidiaryTrust	Dec. 31, 2022 office
Segment Reporting Information [Line Items]
Number of reportable business segments	3		3
Tompkins Insurance Agencies Inc
Segment Reporting Information [Line Items]
Ownership percentage by parent	100.00%	100.00%	100.00%	100.00%
Ithaca, NY
Segment Reporting Information [Line Items]
Number of banking offices		12
Genesee Valley Region
Segment Reporting Information [Line Items]
Number of banking offices		16
Counties North of New York City
Segment Reporting Information [Line Items]
Number of banking offices		13
Southeastern Pennsylvania
Segment Reporting Information [Line Items]
Number of banking offices		19
Western New York
Segment Reporting Information [Line Items]
Nature of operations, number of offices | office				5