Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income attributable to TCF Financial Corporation	$ 22,148	$ 86,196	$ 183,069	$ 218,706
Other comprehensive income (loss), net of tax:
Net unrealized gains (losses) on available for sale investment securities and interest-only strips	19,230	(13,434)	87,223	(46,059)
Net unrealized gains (losses) on net investment hedges	1,641	(1,904)	(2,846)	3,479
Foreign currency translation adjustment	(1,968)	2,899	5,014	(4,136)
Recognized postretirement prior service cost	(9)	(9)	(25)	(26)
Total other comprehensive income (loss), net of tax	18,894	(12,448)	89,366	(46,742)
Comprehensive income	$ 41,042	$ 73,748	$ 272,435	$ 171,964