Accumulated Other Comprehensive Income (Loss) - Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2014
Accumulated Other Comprehensive Income (Loss)
Total other comprehensive income (loss), before tax		$ (14,996)	$ 24,897	$ (30,454)
Total other comprehensive income (loss), tax effect		375	(6,297)	12,075
Total other comprehensive income (loss), net of tax		(14,621)	18,600	(18,379)
Debt securities available for sale and interest-only strips
Net unrealized gains (losses) arising during the period, before tax		(16,373)	24,244	(32,408)
Net unrealized gains (losses) arising during the period, tax effect		4,002	(8,857)	12,323
Net unrealized gains (losses) arising during the period, net of tax		(12,371)	15,387	(20,085)
Reclassification of net (gains) losses from accumulated other comprehensive income (loss), before tax		1,029	208	1,913
Reclassification of net (gains) losses from accumulated other comprehensive income (loss), tax effect		(327)	859	(722)
Reclassification of net (gains) losses from accumulated other comprehensive income (loss), net of tax		702	1,067	1,191
Net unrealized gains (losses) on debt securities available for sale and interest-only strips, before taxes		(15,344)	24,452	(30,495)
Net unrealized gains (losses) on debt securities available for sale and interest-only strips, tax effect		3,675	(7,998)	11,601
Net unrealized gains (losses) on debt securities available for sale and interest-only strips		(11,669)	16,454	(18,894)
Net investment hedges
Net unrealized gains (losses) on net investment hedges, before tax		13,762	(4,430)	(1,213)
Net unrealized gains (losses) on net investment hedges, tax effect		(3,312)	1,684	457
Net unrealized gains (losses) on net investment hedges, net of tax		10,450	(2,746)	(756)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax [Abstract]
Foreign currency translation adjustment, before tax	[1]	(13,368)	4,921	1,300
Foreign currency translation adjustment, tax effect	[1]	0	0	0
Foreign currency translation adjustment, net of tax	[1]	(13,368)	4,921	1,300
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax [Abstract]
Reclassification of amortization of prior service cost to Other non-interest expense, before tax		(46)	(46)	(46)
Reclassification of amortization of prior service cost to Other non-interest expense, tax effect		12	17	17
Reclassification of amortization of prior service cost to Other non-interest expense, net of tax		(34)	(29)	(29)
Available for sale securities transferred to held to maturity securities value					$ 191,700
Unrealized holding gain (loss) transfers from available for sale to held to maturity retained in accumulated other comprehensive income		11,000	12,100
Total interest income
Debt securities available for sale and interest-only strips
Reclassification of net (gains) losses from accumulated other comprehensive income (loss), before tax		1,066	963	1,764
Reclassification of net (gains) losses from accumulated other comprehensive income (loss), tax effect		(335)	572	(665)
Reclassification of net (gains) losses from accumulated other comprehensive income (loss), net of tax		731	1,535	1,099
Gains (losses) on debt securities, net
Debt securities available for sale and interest-only strips
Reclassification of net (gains) losses from accumulated other comprehensive income (loss), before tax		(127)
Reclassification of net (gains) losses from accumulated other comprehensive income (loss), tax effect		31
Reclassification of net (gains) losses from accumulated other comprehensive income (loss), net of tax		(96)
Other non-interest expense
Debt securities available for sale and interest-only strips
Reclassification of net (gains) losses from accumulated other comprehensive income (loss), before tax		90	(755)	149
Reclassification of net (gains) losses from accumulated other comprehensive income (loss), tax effect		(23)	287	(57)
Reclassification of net (gains) losses from accumulated other comprehensive income (loss), net of tax		$ 67	$ (468)	$ 92

[1] Foreign investments are deemed to be permanent in nature and, therefore, TCF does not provide for taxes on foreign currency translation adjustments.