Long-Term Debt (Schedule Of Trust Preferred Securities) (Details) (USD $) In Thousands, unless otherwise specified			12 Months Ended						0 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013 Amegy Trust I [Member]	Dec. 31, 2013 Amegy Trust II [Member]	Dec. 31, 2013 Amegy Trust III [Member]	Dec. 31, 2013 Stockmen's Trust II [Member]	Dec. 31, 2013 Stockmen's Trust III [Member]	Dec. 31, 2013 Intercontinental Statutory Trust I [Member]	Dec. 31, 2012 Effective Interest Rate [Member] Amegy Trust I [Member]		Dec. 31, 2012 Effective Interest Rate [Member] Amegy Trust II [Member]		Dec. 31, 2012 Effective Interest Rate [Member] Amegy Trust III [Member]		Dec. 31, 2012 Effective Interest Rate [Member] Stockmen's Trust II [Member]		Dec. 31, 2012 Effective Interest Rate [Member] Stockmen's Trust III [Member]		Dec. 31, 2012 Effective Interest Rate [Member] Intercontinental Statutory Trust I [Member]		Dec. 31, 2012 Contractual Interest Rate [Member] Amegy Trust I [Member]		Dec. 31, 2012 Contractual Interest Rate [Member] Amegy Trust II [Member]		Dec. 31, 2012 Contractual Interest Rate [Member] Amegy Trust III [Member]		Dec. 31, 2012 Contractual Interest Rate [Member] Stockmen's Trust II [Member]		Dec. 31, 2012 Contractual Interest Rate [Member] Stockmen's Trust III [Member]		Dec. 31, 2012 Contractual Interest Rate [Member] Intercontinental Statutory Trust I [Member]
Subordinated Borrowing [Line Items]
Junior subordinated debentures related to trust preferred securities	$ 168,043	$ 461,858	$ 51,547	$ 36,083	$ 61,856	$ 7,732	$ 7,732	$ 3,093
Interest rate									3.09%	[1]	2.14%	[1]	2.02%	[1]	3.40%	[1]	3.13%	[1]	3.09%	[1]
Stated/contractual Interest Rate																					3mL+2.85%	[1]	3mL+1.90%	[1]	3mL+1.78%	[1]	3mL+3.15%	[1]	3mL+2.89%	[1]	3mL+2.85%	[1]
Maturity			Dec. 01, 2033	Oct. 01, 2034	Dec. 01, 2034	Mar. 01, 2033	Mar. 01, 2034	Mar. 01, 2034

[1] Designation of “3mL” is three-month LIBOR; effective interest rate at the beginning of the accrual period commencing on or before December 31, 2013 is shown in parenthesis.