Loans And Allowance For Credit Losses (Summary Of Net Financial Impact On Interest Income Due To Interest Rate Modifications Below Market For Accruing TDR Loans) (Details) - USD ($) $ in Thousands		3 Months Ended		12 Months Ended
		Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		$ 6,746	$ 2,424	$ 180,300	$ 74,500
Loans and Leases Receivable, Gross, Consumer, Home Equity		2,432,632		2,432,632		$ 2,416,357
Net financial impact on interest income		438	594
Commercial [Member]
Financing Receivable, Modifications [Line Items]
Net financial impact on interest income		122	169
Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Net financial impact on interest income		(1)	(37)
Consumer Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Home Equity		2,432,632		2,432,632		2,416,357
Net financial impact on interest income		236	279
Commercial and Industrial Sector [Member]
Financing Receivable, Modifications [Line Items]
Net financial impact on interest income		(73)	(57)
Owner Occupied [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		3,594	986
Net financial impact on interest income		(49)	(112)
Commercial Loan [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		6,586	1,030
Term [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		0	0
Net financial impact on interest income		(79)	(109)
One Through Four Family Residential [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		160	110
Net financial impact on interest income		(230)	(271)
Construction And Other Consumer Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		0	0
Net financial impact on interest income		(5)	(7)
Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		0	1,284
Net financial impact on interest income		80	146
Home Equity Line of Credit [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		0	0
Net financial impact on interest income		(1)	(1)
Consumer Loan [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		160	110
Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		3,396	2,314
Nonaccruing [Member] | Owner Occupied [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		244	986
Nonaccruing [Member] | Commercial Loan [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		3,236	1,030
Nonaccruing [Member] | Term [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		0	0
Nonaccruing [Member] | One Through Four Family Residential [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		160	0
Nonaccruing [Member] | Construction And Other Consumer Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		0	0
Nonaccruing [Member] | Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		0	1,284
Nonaccruing [Member] | Home Equity Line of Credit [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		0	0
Nonaccruing [Member] | Consumer Loan [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		160	0
Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		3,350	110
Accruing [Member] | Owner Occupied [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		3,350	0
Accruing [Member] | Commercial Loan [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		3,350	0
Accruing [Member] | Term [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		0	0
Accruing [Member] | One Through Four Family Residential [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		0	110
Loans and Leases Receivable, Gross, Consumer, Home Equity		16,373		16,373		15,421
Accruing [Member] | Construction And Other Consumer Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		0	0
Accruing [Member] | Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		0	0
Accruing [Member] | Home Equity Line of Credit [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		0	0
Accruing [Member] | Consumer Loan [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		0	$ 110
Accruing [Member] | Principal Forgiveness [Member] | One Through Four Family Residential [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Home Equity		10,570		10,570		9,763
Accruing [Member] | Interest Rate Below Market [Member] | One Through Four Family Residential [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Home Equity		198		198		192
Accruing [Member] | Maturity Or Team Extension [Member] | One Through Four Family Residential [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Home Equity		2,414		2,414		2,147
Accruing [Member] | Payment Deferral [Member] | One Through Four Family Residential [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Home Equity		0		0		0
Accruing [Member] | Other Recorded Investment Resulting From Following Modification [Member] | One Through Four Family Residential [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Home Equity	[1]	164		164		164
Accruing [Member] | Multiple Modification Types [Member] | One Through Four Family Residential [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Home Equity	[2]	$ 3,027		$ 3,027		$ 3,155

[1] 1 Includes TDRs that resulted from other modification types including, but not limited to, a legal judgment awarded on different terms, a bankruptcy plan confirmed on different terms, a settlement that includes the delivery of collateral in exchange for debt reduction, etc.

[2] 2 Includes TDRs that resulted from a combination of any of the previous modification types.