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Basis of Presentation (Details)	12 Months Ended
Basis of Presentation (Details)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Auto Finance Strategic Shift
Goodwill impairment	$ 0	$ 73,041,000	$ 0
Other intangible assets impairment charge	$ 0	368,000	$ 0
Restructuring expenses related to severance, other asset impairments and lease terminations		$ 14,800,000
Consumer banking services
Product Information
Number of states in which TCF provides services and products	47
Commercial banking services
Product Information
Number of states in which TCF provides services and products	42
Commercial leasing and equipment financing
Product Information
Number of states in which TCF provides services and products	50
Commercial inventory financing
Product Information
Number of states in which TCF provides services and products	50