Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities
Net income	$ 306,926	$ 315,628	$ 278,784
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Provision for credit losses	65,282	46,768	68,443
Share-based compensation expense	28,351	17,824	14,743
Depreciation and amortization	308,638	204,778	191,824
Impairment of goodwill and other intangible assets	0	0	73,409
Provision (benefit) for deferred income taxes	30,410	58,986	(53,729)
Net gains on sales of assets	(66,298)	(39,881)	(51,965)
Proceeds from sales of loans and leases held-for-sale	966,352	372,354	280,640
Originations of loans and leases held-for-sale, net of repayments	(835,047)	(375,622)	(430,121)
Impairment of loan servicing rights	3,882	0	0
Net change in other assets	(263,351)	(35,154)	(108,700)
Net change in other liabilities	162,533	39,898	17,826
Other, net	(65,921)	(41,949)	(36,196)
Net cash provided by (used in) operating activities	641,757	563,630	244,958
Cash flows from investing activities
Proceeds from sales of investment securities available-for-sale	1,986,386	254,146	0
Proceeds from maturities of and principal collected on investment securities available-for-sale	735,861	169,622	116,358
Purchases of investment securities available-for-sale	(2,806,598)	(1,230,430)	(353,557)
Proceeds from maturities of and principal collected on investment securities held-to-maturity	17,632	15,407	21,186
Purchases of investment securities held-to-maturity	(6,844)	(2,188)	(1,051)
Redemption of Federal Home Loan Bank stock	256,021	269,002	246,002
Purchases of Federal Home Loan Bank stock	(370,000)	(278,000)	(254,000)
Proceeds from sales of loans and leases	1,985,093	903,606	1,618,791
Loan and lease originations and purchases, net of principal collected	(2,037,489)	(957,672)	(2,726,967)
Proceeds from sales of other assets	113,771	88,942	63,875
Proceeds from sales of other assets	(154,540)	(155,664)	(168,272)
Net cash acquired (paid) in business combinations	975,014	0
Net cash acquired (paid) in business combinations			(8,120)
Other, net	(27,431)	20,935	26,103
Net cash provided by (used in) investing activities	666,876	(902,294)	(1,419,652)
Cash flows from financing activities
Net change in deposits	(901,522)	549,157	1,094,612
Net change in short-term borrowings	45,584	160	(4,747)
Proceeds from long-term borrowings	5,957,492	9,380,950	9,990,967
Payments on long-term borrowings	(5,499,669)	(9,182,536)	(9,816,286)
Payments on liabilities related to acquisition and portfolio purchase	(1,000)	(2,000)	(3,000)
Redemption of Series B preferred stock	0	(100,000)	0
Net proceeds from public offering of Series C preferred stock	0	0	169,302
Proceeds preferred stock	0	0	(172,500)
Repurchases of common stock	(86,309)	(212,929)	(9,163)
Common shares sold to TCF employee benefit plans	0	715	23,254
Dividends paid on preferred stock	(9,975)	(11,588)	(19,904)
Dividends paid on common stock	(156,060)	(99,490)	(50,617)
Exercise of stock options	29	(997)	(57)
Payments related to tax-withholding upon conversion of share-based awards	(6,198)	(6,865)	(5,506)
Net investment by (distribution to) non-controlling interest	(9,691)	(10,638)	(9,482)
Net cash provided by (used in) financing activities	(667,319)	303,939	1,186,873
Net change in cash and due from banks	641,314	(34,725)	12,179
Cash and cash equivalents at beginning of period	587,057	621,782	609,603
Cash and cash equivalents at end of period	1,228,371	587,057	621,782
Cash paid (received) for:
Interest on deposits and borrowings	269,474	139,026	86,411
Income taxes, net	12,177	(26,308)	62,115
Noncash activities:
Transfer of loans and leases to other assets	88,716	105,247	100,608
Transfer of loans and leases from held for investment to held for sale, net	$ 2,184,134	$ 848,941	$ 1,320,210