Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income attributable to TCF Financial Corporation	$ 295,468	$ 304,358	$ 268,637
Other comprehensive income (loss), net of tax:
Net unrealized gains (losses) on available-for-sale investment securities and interest-only strips	84,120	(11,669)	16,454
Net unrealized gains (losses) on net investment hedges	(5,186)	10,450	(2,746)
Foreign currency translation adjustment	8,514	(13,368)	4,921
Recognized postretirement prior service cost	(33)	(34)	(29)
Total other comprehensive income (loss), net of tax	87,415	(14,621)	18,600
Comprehensive income	$ 382,883	$ 289,737	$ 287,237

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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