Parent Company Financial Information - Condensed Statements of Financial Condition (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Assets:
Cash and due from banks	$ 587,057	$ 621,782	$ 609,603	$ 889,337
Other assets	814,164	782,552
Total assets	23,699,612	23,002,159	21,441,326
Liabilities and Equity:
Total liabilities	21,143,352	20,321,575
Equity	2,537,801	2,662,757
Total liabilities and equity	23,699,612	23,002,159
TCF Financial Corporation
Assets:
Cash and due from banks	91,132	80,471	$ 69,711	$ 69,503
Investment in TCF Bank	2,426,329	2,563,552
Accounts receivable from TCF Bank	23,780	22,015
Other assets	4,253	5,739
Total assets	2,545,494	2,671,777
Liabilities and Equity:
Accrued expenses and other liabilities	7,693	9,020
Total liabilities	7,693	9,020
Equity	2,537,801	2,662,757
Total liabilities and equity	$ 2,545,494	$ 2,671,777