Variable Interest Entities (Summary Of VIE Consolidated By FHN) (Details) - USD ($) $ in Thousands	Sep. 30, 2017		Jun. 30, 2017	Dec. 31, 2016		Sep. 30, 2016	Jun. 30, 2016	Dec. 31, 2015
Assets:
Cash and due from banks	$ 347,802			$ 373,274
Loans, net of unearned income	20,166,091	[1]		19,589,520	[1]	$ 19,555,787
Less: Allowance for loan losses	194,867		$ 197,257	202,068		$ 201,557	$ 199,807	$ 210,242
Total net loans	19,971,224			19,387,452
Total assets	1,441,878			1,406,711
Total assets	29,622,636			28,555,231
Liabilities:
Term borrowings	1,059,507			1,040,656
Other liabilities	426,910			467,944
Total liabilities	26,739,085			25,850,147
On Balance Sheet Consumer Loan Securitizations
Assets:
Cash and due from banks	0			0
Loans, net of unearned income	26,210			35,873
Less: Allowance for loan losses	0			587
Total net loans	26,210			35,286
Total assets	47			283
Total assets	26,257			35,569
Liabilities:
Term borrowings	13,354			23,126
Other liabilities	3			3
Total liabilities	13,357			23,129
Rabbi Trusts Used For Deferred Compensation Plans
Assets:
Total assets	77,997			74,160
Total assets	77,997			74,160
Liabilities:
Other liabilities	58,785			54,746
Total liabilities	$ 58,785			$ 54,746

[1] September 30, 2017 and December 31, 2016 include $24.8 million and $28.5 million, respectively, of held-to-maturity consumer mortgage loans secured by residential real estate properties in process of foreclosure.