Investment Securities (Details 2) (USD $) In Thousands	Jun. 30, 2011
Debt securities available for sale:
Due in one year or less	$ 26,403
Due after one year through five years	119,212
Due after five years through ten years	16,687
Due after ten years	278,323
Available For Sale Securities Debt Maturities With Single Maturity Date Amortized Cost	440,625
Mortgage-backed securities available for sale	4,493,876
Total	4,934,501
Debt securities available for sale:
Due in one year or less	26,521
Due after one year through five years	121,204
Due after five years through ten years	18,081
Due after ten years	271,775
Available For Sale Securities Debt Maturities With Single Maturity Date Fair Value	437,581
Mortgage-backed securities available for sale	4,346,453
Total	4,784,034
Debt securities held to maturity:
Due in one year or less	23,428
Due after one year through five years	20,126
Due after five years through ten years	134,952
Due after ten years	18,361
Held To Maturity Securities Debt Maturities With Single Maturity Date Net Carrying Amount	196,867
Mortgage-backed securities held to maturity	1,022,819
Total	1,219,686
Debt securities held to maturity:
Due in one year or less	23,607
Due after one year through five years	20,775
Due after five years through ten years	138,114
Due after ten years	18,461
Held To Maturity Securities Debt Maturities With Single Maturity Date Fair Value	200,957
Mortgage-backed securities held to maturity	942,539
Total	$ 1,143,496

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