Parent Company Financial Information - Condensed Statements of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Condensed Statements of Cash Flows
Net income	$ 304,358	$ 268,637	$ 212,124
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	222,602	206,567	182,226
Provision (benefit) for deferred income taxes	58,986	(53,729)	32,966
Gains on sales of assets, net	(39,881)	(51,965)	(97,383)
Net change in other assets and accrued expenses and other liabilities	(2,121)	(96,380)	71,495
Other, net	(41,949)	(36,196)	(24,667)
Cash flows from investing activities:
Purchases of premises and equipment	(56,091)	(48,428)	(34,513)
Proceeds from sales of assets	88,942	63,875	76,885
Cash flows from financing activities:
Net proceeds from public offering of Series C preferred stock	0	169,302	0
Repurchases of common stock	(212,929)	(9,163)	0
Common shares sold to TCF employee benefit plans	715	23,254	5,838
Dividends paid on preferred stock	(11,588)	(19,904)	(19,388)
Dividends paid on common stock	(99,490)	(50,617)	(50,182)
Stock compensation tax (expense) benefit	0	0	(377)
Exercise of stock options	(997)	(57)	(701)
Net change in cash and due from banks	(34,725)	12,179	(279,734)
Cash and due from banks at beginning of period	621,782	609,603	889,337
Cash and due from banks at end of period	587,057	621,782	609,603
Series B Preferred Stock
Cash flows from financing activities:
Redemption of preferred stock	(100,000)	0	0
Series A Preferred Stock
Cash flows from financing activities:
Redemption of preferred stock	0	(172,500)	0
TCF Financial Corporation
Condensed Statements of Cash Flows
Net income	304,358	268,637	212,124
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Equity in undistributed earnings (loss) of TCF Bank	122,487	(206,067)	(151,790)
Depreciation and amortization	4,986	9,110	4,734
Provision (benefit) for deferred income taxes	(583)	4,690	(592)
Gains on sales of assets, net	(402)	0	0
Net change in other assets and accrued expenses and other liabilities	379	(2,494)	1,032
Other, net	3,001	(3,408)	(443)
Net cash provided by (used in) operating activities	434,226	70,468	65,065
Cash flows from investing activities:
Purchases of premises and equipment	(3)	(23)	(69)
Proceeds from sales of assets	727	0	22
Net cash provided by (used in) investing activities	724	(23)	(47)
Cash flows from financing activities:
Net proceeds from public offering of Series C preferred stock	0	169,302	0
Repurchases of common stock	(212,929)	(9,163)	0
Common shares sold to TCF employee benefit plans	715	23,254	5,838
Dividends paid on preferred stock	(11,588)	(19,904)	(19,388)
Dividends paid on common stock	(99,490)	(50,617)	(50,182)
Stock compensation tax (expense) benefit	0	0	(377)
Exercise of stock options	(997)	(57)	(701)
Net cash provided by (used in) financing activities	(424,289)	(59,685)	(64,810)
Net change in cash and due from banks	10,661	10,760	208
Cash and due from banks at beginning of period	80,471	69,711	69,503
Cash and due from banks at end of period	91,132	80,471	69,711
TCF Financial Corporation | Series B Preferred Stock
Cash flows from financing activities:
Redemption of preferred stock	(100,000)	0	0
TCF Financial Corporation | Series A Preferred Stock
Cash flows from financing activities:
Redemption of preferred stock	0	$ (172,500)	$ 0
TCF Bank
Condensed Statements of Cash Flows
Net profits for the current year combined with retained net profits for preceding two calendar years	$ 235,400