Investment Securities (Schedule Of FHN's Investment Securities) (Details) - USD ($) $ in Thousands		6 Months Ended		12 Months Ended
		Jun. 30, 2017		Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, Amortized Cost		$ 3,964,419		$ 3,971,435	[1]
Securities available for sale, Gross Unrealized Gains	[1]			19,869
Securities available for sale, Gross Unrealized Losses	[1]			(47,805)
Securities available-for-sale		3,949,592	[2]	3,943,499	[1]
Pledged available for sale securities		3,500,000		3,300,000
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, Amortized cost		10,000		14,347
Securities held to maturity, Gross Unrealized Gains		0		426
Securities held to maturity, Gross Unrealized Losses		(9)		0
Held-to-maturity Securities, Fair Value		9,991		14,773
FRB
Schedule of Available-for-sale Securities [Line Items]
Restricted investments		68,600		68,600
FHLB-Cincinnati Stock
Schedule of Available-for-sale Securities [Line Items]
Restricted investments		87,900		87,900
SBA - Interest Only Strips
Schedule of Available-for-sale Securities [Line Items]
Securities available-for-sale	[3]	1,163
States And Municipalities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, Amortized cost				4,347
Securities held to maturity, Gross Unrealized Gains				393
Securities held to maturity, Gross Unrealized Losses				0
Held-to-maturity Securities, Fair Value				4,740
Corporate Bonds
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, Amortized cost		10,000		10,000
Securities held to maturity, Gross Unrealized Gains		0		33
Securities held to maturity, Gross Unrealized Losses		(9)		0
Held-to-maturity Securities, Fair Value		9,991		10,033
U.S. treasuries
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, Amortized Cost		100		100
Securities available for sale, Gross Unrealized Gains		0		0
Securities available for sale, Gross Unrealized Losses		0		0
Securities available-for-sale		100		100
Government Agency Issued Mortgage-Backed Securities ("MBS")
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, Amortized Cost		2,130,894		2,217,593
Securities available for sale, Gross Unrealized Gains		13,160		14,960
Securities available for sale, Gross Unrealized Losses		(14,438)		(23,866)
Securities available-for-sale		2,129,616		2,208,687
Government Agency Issued Collateralized Mortgage Obligations ("CMO")
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, Amortized Cost		1,646,533		1,566,986
Securities available for sale, Gross Unrealized Gains		4,754		4,909
Securities available for sale, Gross Unrealized Losses		(19,464)		(23,937)
Securities available-for-sale		1,631,823		1,547,958
Equity and other
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, Amortized Cost		186,892	[4]	186,756	[5]
Securities available for sale, Gross Unrealized Gains		0	[4]	0	[5]
Securities available for sale, Gross Unrealized Losses		(2)	[4]	(2)	[5]
Securities available-for-sale		186,890	[4]	$ 186,754	[5]
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, Amortized cost		0
Held-to-maturity Securities, Fair Value		0
Securities available-for-sale, excluding interest only strip:
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, Amortized Cost		3,964,419
Securities available for sale, Gross Unrealized Gains		17,914
Securities available for sale, Gross Unrealized Losses		(33,904)
Securities available-for-sale		$ 3,948,429

[1] Includes $3.3 billion of securities pledged to secure public deposits, securities sold under agreements to repurchase, and for other purposes.

[2] Includes $3.5 billion of securities pledged to secure public deposits, securities sold under agreements to repurchase, and for other purposes.

[3] SBA-interest only strips are recorded at elected fair value. See Note 16 - Fair Value for additional information.

[4] Includes restricted investments in FHLB-Cincinnati stock of $87.9 million and FRB stock of $68.6 million. The remainder is money market, mutual funds, and cost method investments.

[5] Includes restricted investments in FHLB-Cincinnati stock of $87.9 million and FRB stock of $68.6 million. The remainder is money market, mutual funds, and cost method investments.