Quarterly report pursuant to Section 13 or 15(d)

Held-to-Maturity Securities (Details)

v2.4.0.6
Held-to-Maturity Securities (Details) (USD $)
In Thousands, unless otherwise specified
Sep. 30, 2012
Dec. 31, 2011
Contractual maturities of held-to-maturity securities    
Held-to-maturity securities, Total $ 1,582,150 $ 640,551
Held-to-maturity Securities, Fair Value 1,624,970 660,186
Amortized cost, gross unrealized gains and losses, and fair value by investment category    
Held-to-maturity securities, Total 1,582,150 640,551
Held-to-maturity Securities, Gross Gain 42,820 19,652
Held-to-maturity Securities, Gross Losses 0 (17)
Held-to-maturity securities, fair value 1,624,970 660,186
Federal agencies - mortgage backed securities [Member]
    
Contractual maturities of held-to-maturity securities    
Held-to-maturity Securities, Under 1 year 0 0
Held-to-maturity Securities, 1-5 years 0 0
Held-to-maturity Securities, 6-10 years 0 0
Held-to-maturity Securities, Over 10 years 1,506,139 640,551
Held-to-maturity securities, Total 1,506,139 640,551
Fair Value, Under 1 year 0 0
Fair Value, 1-5 years 0 0
Fair Value, 6-10 years 0 0
Fair Value, Over 10 years 1,548,303 660,186
Held-to-maturity Securities, Fair Value 1,548,303 660,186
Amortized cost, gross unrealized gains and losses, and fair value by investment category    
Held-to-maturity securities, Total 1,506,139 640,551
Held-to-maturity Securities, Gross Gain 42,164 19,652
Held-to-maturity Securities, Gross Losses 0 (17)
Held-to-maturity securities, fair value 1,548,303 660,186
Other Federal Agencies [Member]
    
Contractual maturities of held-to-maturity securities    
Held-to-maturity Securities, Under 1 year 0 0
Held-to-maturity Securities, 1-5 years 0 0
Held-to-maturity Securities, 6-10 years 0 0
Held-to-maturity Securities, Over 10 years 76,011 0
Held-to-maturity securities, Total 76,011 0
Fair Value, Under 1 year 0 0
Fair Value, 1-5 years 0 0
Fair Value, 6-10 years 0 0
Fair Value, Over 10 years 76,667 0
Held-to-maturity Securities, Fair Value 76,667 0
Amortized cost, gross unrealized gains and losses, and fair value by investment category    
Held-to-maturity securities, Total 76,011 0
Held-to-maturity Securities, Gross Gain 656 0
Held-to-maturity Securities, Gross Losses 0 0
Held-to-maturity securities, fair value 76,667 0
Total U.S. Government backed agencies [Member]
    
Contractual maturities of held-to-maturity securities    
Held-to-maturity securities, Total 1,582,150 640,551
Held-to-maturity Securities, Fair Value 1,624,970 660,186
Amortized cost, gross unrealized gains and losses, and fair value by investment category    
Held-to-maturity securities, Total 1,582,150 640,551
Held-to-maturity Securities, Gross Gain 42,820 19,652
Held-to-maturity Securities, Gross Losses 0 (17)
Held-to-maturity securities, fair value $ 1,624,970 $ 660,186