The average effective interest rate during the reporting period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Long-Term Debt (Schedule Of Trust Preferred Securities) (Details) - USD ($) $ in Thousands		12 Months Ended
	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015
Subordinated Borrowing [Line Items]
Junior subordinated debentures related to trust preferred securities	$ 0	$ 0	$ 164,950
Amegy Trust I [Member]
Subordinated Borrowing [Line Items]
Maturity		Sep. 17, 2016
AMEGY STATUTORY TRUST ONE [Member]
Subordinated Borrowing [Line Items]
Junior subordinated debentures related to trust preferred securities	$ 0	$ 0	51,547
Coupon Rate	3mL+2.85% (3.38%)
Amegy Trust II [Member]
Subordinated Borrowing [Line Items]
Maturity		Oct. 07, 2016
AMEGY STATUTORY TRUSTS 2 [Member]
Subordinated Borrowing [Line Items]
Junior subordinated debentures related to trust preferred securities	$ 0	$ 0	36,083
Coupon Rate	3mL+1.90% (2.22%)
Amegy Trust III [Member]
Subordinated Borrowing [Line Items]
Maturity		Sep. 15, 2016
AMEGY STATUTORY TRUSTS 3 [Member] [Member]
Subordinated Borrowing [Line Items]
Junior subordinated debentures related to trust preferred securities	$ 0	$ 0	61,856
Coupon Rate	3mL+1.78% (2.29%)
Stockmen's Trust II [Member]
Subordinated Borrowing [Line Items]
Maturity		Sep. 26, 2016
STOCKMEN S STATUTORY TRUST 2 [Member]
Subordinated Borrowing [Line Items]
Junior subordinated debentures related to trust preferred securities	$ 0	$ 0	7,732
Coupon Rate	3mL+3.15% (3.75%)
Stockmen's Trust III [Member]
Subordinated Borrowing [Line Items]
Maturity		Sep. 17, 2016
STOCKMEN S STATUTORY TRUST 3 [Member]
Subordinated Borrowing [Line Items]
Junior subordinated debentures related to trust preferred securities	$ 0	$ 0	$ 7,732
Coupon Rate	3mL+2.89% (3.42%)
Effective Interest Rate [Member] \| Amegy Trust I [Member]
Subordinated Borrowing [Line Items]
Interest rate	3.38%
Effective Interest Rate [Member] \| Amegy Trust II [Member]
Subordinated Borrowing [Line Items]
Interest rate	2.22%
Effective Interest Rate [Member] \| Amegy Trust III [Member]
Subordinated Borrowing [Line Items]
Interest rate	2.29%
Effective Interest Rate [Member] \| Stockmen's Trust II [Member]
Subordinated Borrowing [Line Items]
Interest rate	3.75%
Effective Interest Rate [Member] \| Stockmen's Trust III [Member]
Subordinated Borrowing [Line Items]
Interest rate	3.42%
Contractual Interest Rate [Member] \| Amegy Trust I [Member]
Subordinated Borrowing [Line Items]
Stated/contractual Interest Rate	3mL+2.85%
Contractual Interest Rate [Member] \| Amegy Trust II [Member]
Subordinated Borrowing [Line Items]
Stated/contractual Interest Rate	3mL+1.90%
Contractual Interest Rate [Member] \| Amegy Trust III [Member]
Subordinated Borrowing [Line Items]
Stated/contractual Interest Rate	3mL+1.78%
Contractual Interest Rate [Member] \| Stockmen's Trust II [Member]
Subordinated Borrowing [Line Items]
Stated/contractual Interest Rate	3mL+3.15%
Contractual Interest Rate [Member] \| Stockmen's Trust III [Member]
Subordinated Borrowing [Line Items]
Stated/contractual Interest Rate	3mL+2.89%