Variable Interest Entities - Summary Of VIE Consolidated By FHN (Details) - USD ($) $ in Thousands	Mar. 31, 2019		Dec. 31, 2018		Mar. 31, 2018	Dec. 31, 2017
Assets:
Cash and due from banks	$ 570,589		$ 781,291
Loans, net of unearned income	27,990,048	[1]	27,535,532	[1]	$ 27,249,793
Less: Allowance for loan losses	184,911		180,424		$ 187,194	$ 189,555
Total net loans	27,805,137		27,355,108
Total assets	1,910,626		1,802,939
Total assets	41,099,003		40,832,258
Liabilities:
Term borrowings	1,177,926		1,170,963
Other liabilities	748,606		580,335
Total liabilities	36,252,482		36,046,878
On-Balance Sheet Consumer Loan Securitization
Assets:
Cash and due from banks	0		0
Loans, net of unearned income	14,990		16,213
Less: Allowance for loan losses	0		0
Total net loans	14,990		16,213
Total assets	34		35
Total assets	15,024		16,248
Liabilities:
Term borrowings	1,802		2,981
Other liabilities	0		0
Total liabilities	1,802		2,981
Rabbi Trusts Used for Deferred Compensation Plans
Assets:
Total assets	83,941		78,446
Total assets	83,941		78,446
Liabilities:
Other liabilities	64,069		56,700
Total liabilities	$ 64,069		$ 56,700

[1] March 31, 2019 and December 31, 2018 include $24.1 million and $28.6 million, respectively, of held-to-maturity consumer mortgage loans secured by residential real estate in process of foreclosure.