Components of Other Comprehensive Income/(loss) (Schedule of Changes in AOCI) (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance		$ (247,654)	$ (214,192)
Net unrealized gains/(losses)		(2,598)	44,019
Amounts reclassifed from AOCI		294	(268)
Other comprehensive income/(loss)	[1]	(2,304)	43,751
Ending Balance		(249,958)	(170,441)
Securities AFS
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance		(17,232)	3,394
Net unrealized gains/(losses)		(1,536)	40,180
Amounts reclassifed from AOCI		(27)	(1,020)
Other comprehensive income/(loss)		(1,563)	39,160
Ending Balance		(18,795)	42,554
Cash Flow Hedges
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance		(1,265)	0
Net unrealized gains/(losses)		(1,062)	3,839
Amounts reclassifed from AOCI		(852)	(374)
Other comprehensive income/(loss)		(1,914)	3,465
Ending Balance		(3,179)	3,465
Pension and Postretirement Plans
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance		(229,157)	(217,586)
Net unrealized gains/(losses)		0	0
Amounts reclassifed from AOCI		1,173	1,126
Other comprehensive income/(loss)		1,173	1,126
Ending Balance		$ (227,984)	$ (216,460)

[1] Due to the nature of the preferred stock issued by FHN and its subsidiaries, all components of Other comprehensive income/(loss) have been attributed solely to FHN as the controlling interest holder.