Fair Values Disclosures - Assets and Liabilities Measured at Fair Value (Details) - USD ($)		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Adjustment Disclosure
Transfers between fair value levels		$ 0	$ 0	$ 0
Measurement of fair value on a recurring basis
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		63,709,000	35,406,000
Liabilities, Fair value carrying amount		37,751,000	36,889,000
Measurement of fair value on a recurring basis | Level 1
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		33,217,000	29,962,000
Liabilities, Fair value carrying amount		33,217,000	29,962,000
Measurement of fair value on a recurring basis | Level 2
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		11,618,000	1,797,000
Liabilities, Fair value carrying amount		3,745,000	6,307,000
Measurement of fair value on a recurring basis | Level 3
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		18,874,000	3,647,000
Liabilities, Fair value carrying amount		789,000	620,000
Measurement of fair value on a recurring basis | Loans held for sale
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		18,070,000	3,356,000
Measurement of fair value on a recurring basis | Loans held for sale | Level 1
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		0	0
Measurement of fair value on a recurring basis | Loans held for sale | Level 2
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		0	0
Measurement of fair value on a recurring basis | Loans held for sale | Level 3
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		18,070,000	3,356,000
Measurement of fair value on a recurring basis | Interest rate contracts
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount	[1]	7,909,000	1,797,000
Liabilities, Fair value carrying amount	[1]	3,732,000	1,688,000
Measurement of fair value on a recurring basis | Interest rate contracts | Level 1
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount	[1]	0	0
Liabilities, Fair value carrying amount	[1]	0	0
Measurement of fair value on a recurring basis | Interest rate contracts | Level 2
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount	[1]	7,909,000	1,797,000
Liabilities, Fair value carrying amount	[1]	3,732,000	1,688,000
Measurement of fair value on a recurring basis | Interest rate contracts | Level 3
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount	[1]	0	0
Liabilities, Fair value carrying amount	[1]	0	0
Measurement of fair value on a recurring basis | Forward foreign exchange contracts
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount	[1]	3,709,000
Liabilities, Fair value carrying amount	[1]	13,000	4,619,000
Measurement of fair value on a recurring basis | Forward foreign exchange contracts | Level 1
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount	[1]	0
Liabilities, Fair value carrying amount	[1]	0	0
Measurement of fair value on a recurring basis | Forward foreign exchange contracts | Level 2
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount	[1]	3,709,000
Liabilities, Fair value carrying amount	[1]	13,000	4,619,000
Measurement of fair value on a recurring basis | Forward foreign exchange contracts | Level 3
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount	[1]	0
Liabilities, Fair value carrying amount	[1]	0	0
Measurement of fair value on a recurring basis | Interest rate lock commitments
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount	[1]	652,000	223,000
Liabilities, Fair value carrying amount	[1]	28,000
Measurement of fair value on a recurring basis | Interest rate lock commitments | Level 1
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount	[1]	0	0
Liabilities, Fair value carrying amount	[1]	0
Measurement of fair value on a recurring basis | Interest rate lock commitments | Level 2
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount	[1]	0	0
Liabilities, Fair value carrying amount	[1]	0
Measurement of fair value on a recurring basis | Interest rate lock commitments | Level 3
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount	[1]	652,000	223,000
Liabilities, Fair value carrying amount	[1]	28,000
Measurement of fair value on a recurring basis | Forward loan sales commitments
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		152,000	68,000
Liabilities, Fair value carrying amount		178,000	5,000
Measurement of fair value on a recurring basis | Forward loan sales commitments | Level 1
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		0	0
Liabilities, Fair value carrying amount		0	0
Measurement of fair value on a recurring basis | Forward loan sales commitments | Level 2
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		0	0
Liabilities, Fair value carrying amount		0	0
Measurement of fair value on a recurring basis | Forward loan sales commitments | Level 3
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		152,000	68,000
Liabilities, Fair value carrying amount		178,000	5,000
Measurement of fair value on a recurring basis | Assets held in trust for deferred compensation plans
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		33,217,000	29,962,000
Measurement of fair value on a recurring basis | Assets held in trust for deferred compensation plans | Level 1
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		33,217,000	29,962,000
Measurement of fair value on a recurring basis | Assets held in trust for deferred compensation plans | Level 2
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		0	0
Measurement of fair value on a recurring basis | Assets held in trust for deferred compensation plans | Level 3
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		0	0
Measurement of fair value on a recurring basis | Other contracts
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Liabilities, Fair value carrying amount	[1]	583,000	615,000
Measurement of fair value on a recurring basis | Other contracts | Level 1
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Liabilities, Fair value carrying amount	[1]	0	0
Measurement of fair value on a recurring basis | Other contracts | Level 2
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Liabilities, Fair value carrying amount	[1]	0	0
Measurement of fair value on a recurring basis | Other contracts | Level 3
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Liabilities, Fair value carrying amount	[1]	583,000	615,000
Measurement of fair value on a recurring basis | Liabilities held in trust for deferred compensation plans
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Liabilities, Fair value carrying amount		33,217,000	29,962,000
Measurement of fair value on a recurring basis | Liabilities held in trust for deferred compensation plans | Level 1
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Liabilities, Fair value carrying amount		33,217,000	29,962,000
Measurement of fair value on a recurring basis | Liabilities held in trust for deferred compensation plans | Level 2
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Liabilities, Fair value carrying amount		0	0
Measurement of fair value on a recurring basis | Liabilities held in trust for deferred compensation plans | Level 3
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Liabilities, Fair value carrying amount		0	0
Measurement of fair value on a non-recurring basis
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		76,583,000	94,380,000
Loans		57,663,000	72,287,000
Other real estate owned		9,397,000	14,036,000
Repossessed and returned assets		9,523,000	8,057,000
Measurement of fair value on a non-recurring basis | Level 1
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		0	0
Loans		0	0
Other real estate owned		0	0
Repossessed and returned assets		0	0
Measurement of fair value on a non-recurring basis | Level 2
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		4,358,000	3,669,000
Loans		0	0
Other real estate owned		0	0
Repossessed and returned assets		4,358,000	3,669,000
Measurement of fair value on a non-recurring basis | Level 3
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		72,225,000	90,711,000
Loans		57,663,000	72,287,000
Other real estate owned		9,397,000	14,036,000
Repossessed and returned assets		5,165,000	4,388,000
Other Comprehensive Income (Loss) | Measurement of fair value on a recurring basis
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		2,489,880,000	1,730,404,000
Liabilities, Fair value carrying amount			1,744,000
Other Comprehensive Income (Loss) | Measurement of fair value on a recurring basis | Level 1
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		0	0
Liabilities, Fair value carrying amount			0
Other Comprehensive Income (Loss) | Measurement of fair value on a recurring basis | Level 2
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		2,473,041,000	1,709,012,000
Liabilities, Fair value carrying amount			1,744,000
Other Comprehensive Income (Loss) | Measurement of fair value on a recurring basis | Level 3
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		16,839,000	21,392,000
Liabilities, Fair value carrying amount			0
Other Comprehensive Income (Loss) | Measurement of fair value on a recurring basis | Forward foreign exchange contracts
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		2,980,000
Liabilities, Fair value carrying amount	[1]		1,744,000
Other Comprehensive Income (Loss) | Measurement of fair value on a recurring basis | Forward foreign exchange contracts | Level 1
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		0
Liabilities, Fair value carrying amount	[1]		0
Other Comprehensive Income (Loss) | Measurement of fair value on a recurring basis | Forward foreign exchange contracts | Level 2
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		2,980,000
Liabilities, Fair value carrying amount	[1]		1,744,000
Other Comprehensive Income (Loss) | Measurement of fair value on a recurring basis | Forward foreign exchange contracts | Level 3
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		0
Liabilities, Fair value carrying amount	[1]		0
Other Comprehensive Income (Loss) | Measurement of fair value on a recurring basis | Mortgage-backed securities, U.S. Government sponsored enterprises and federal agencies
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		1,913,190,000	894,685,000
Other Comprehensive Income (Loss) | Measurement of fair value on a recurring basis | Mortgage-backed securities, U.S. Government sponsored enterprises and federal agencies | Level 1
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		0	0
Other Comprehensive Income (Loss) | Measurement of fair value on a recurring basis | Mortgage-backed securities, U.S. Government sponsored enterprises and federal agencies | Level 2
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		1,913,190,000	894,685,000
Other Comprehensive Income (Loss) | Measurement of fair value on a recurring basis | Mortgage-backed securities, U.S. Government sponsored enterprises and federal agencies | Level 3
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		0	0
Other Comprehensive Income (Loss) | Measurement of fair value on a recurring basis | Mortgage-backed securities, Other
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		4,000	6,000
Other Comprehensive Income (Loss) | Measurement of fair value on a recurring basis | Mortgage-backed securities, Other | Level 1
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		0	0
Other Comprehensive Income (Loss) | Measurement of fair value on a recurring basis | Mortgage-backed securities, Other | Level 2
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		0	0
Other Comprehensive Income (Loss) | Measurement of fair value on a recurring basis | Mortgage-backed securities, Other | Level 3
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		4,000	6,000
Other Comprehensive Income (Loss) | Measurement of fair value on a recurring basis | Obligations of states and political subdivisions
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		556,871,000	814,327,000
Other Comprehensive Income (Loss) | Measurement of fair value on a recurring basis | Obligations of states and political subdivisions | Level 1
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		0	0
Other Comprehensive Income (Loss) | Measurement of fair value on a recurring basis | Obligations of states and political subdivisions | Level 2
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		556,871,000	814,327,000
Other Comprehensive Income (Loss) | Measurement of fair value on a recurring basis | Obligations of states and political subdivisions | Level 3
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		0	0
Other Comprehensive Income (Loss) | Measurement of fair value on a recurring basis | Interest only strip
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		16,835,000	21,386,000
Other Comprehensive Income (Loss) | Measurement of fair value on a recurring basis | Interest only strip | Level 1
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		0	0
Other Comprehensive Income (Loss) | Measurement of fair value on a recurring basis | Interest only strip | Level 2
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		0	0
Other Comprehensive Income (Loss) | Measurement of fair value on a recurring basis | Interest only strip | Level 3
Fair Value, Assets and liabilities measured at fair value on Recurring and Nonrecurring basis
Assets, Fair value carrying amount		$ 16,835,000	$ 21,386,000

[1] As permitted under GAAP, TCF has elected to net derivative assets and derivative liabilities when a legally enforceable master netting agreement exists as well as the related cash collateral received and paid. For purposes of this table, the derivative assets and derivative liabilities are presented gross of this netting adjustment.