Securities Purchased Under Agreements To Resell And Collateral Pledged By Company (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2012
Securities Purchased under Agreements to Resell [Abstract]
Gross amounts of recognized assets	$ 576,355		$ 517,263
Gross amounts offset in the Statement of Condition	0		0
Net amounts of assets presented in the Statement of Condition	576,355	601,891	517,263
Offsetting securities sold under agreements to repurchase	(30,584)		(2,068)
Securities collateral (not recognized on FHN's Statement of Condition)	(537,810)		(509,707)
Net amount	$ 7,961		$ 5,488