Federal Home Loan Bank Advances (Summary Of Advances Payable To The Federal Home Loan Bank) (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Total Outstanding	$ 1,452,569	$ 1,251,804
Weighted Average Rate	0.62%	0.99%
Unamortized premiums	91	805
Total Federal Home Loan Bank advances	1,452,660	1,252,609
Year Of Maturity 2012 [Member]
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Total Outstanding	1,000,000	751,400
Weighted Average Rate	0.25%	0.43%
Year Of Maturity 2013 [Member]
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Total Outstanding	150,000	199,000
Weighted Average Rate	0.98%	2.07%
Year Of Maturity 2016 [Member]
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Total Outstanding	145,934	145,934
Weighted Average Rate	1.80%	1.80%
Year Of Maturity 2017-2032 [Member]
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Total Outstanding	$ 156,635	$ 155,470
Weighted Average Rate	1.47%	1.58%

Describes the weighted average interest rate applicable to the specific advances from the Federal Home Loan Bank, by branch, as of the Balance Sheet date.

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Including both current and noncurrent portions, Federal Home Loan Bank borrowings initially due beyond one year or beyond the normal operating cycle if longer.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

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Reference 7: http://www.xbrl.org/2003/role/presentationRef

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- Definition

Amount of federal home loan bank advances. Advances are loans from the federal home loan bank system to a member (shareholder).

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