XML 15 R37.htm IDEA: XBRL DOCUMENT v2.4.0.6
Fair Value Measurements (Reconciliation Of Amortized Cost of Fair Value of Investments) (Details) (USD $)
In Thousands, unless otherwise specified
6 Months Ended 12 Months Ended
Mar. 31, 2013
Mar. 31, 2012
Sep. 30, 2012
Available-for-Sale Securities, Amortized Cost      
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis $ 2,003,858   $ 1,760,668
Available-for-Sale Securities, Gross Unrealized Gains (Losses)      
Available-for-sale Securities, Gross Unrealized Gains 20,308   22,161
Available-for-sale Securities, Gross Unrealized Losses 1,498   1,124
Available-for-Sale Securities, Fair Value      
Available-for-sale Securities, Debt Securities 2,022,668   1,781,705
Available-for-Sale Securities, Yield      
Available-for-sale Securities, Yield 1.61%   1.99%
Held-to-maturity Securities, Yield 3.04%   3.10%
Yield 2.22%   2.44%
Held-to-Maturity Securities, Amortized Cost      
Held-to-maturity Securities, Debt Maturities, Net Carrying Amount 1,469,983   1,191,487
Held-to-Maturity Securities, Gross Unrealized Gains      
Held-to-maturity Securities, Unrecognized Holding Gain 3,302   25,736
Held-to-Maturity Securities, Gross Unrealized Losses      
Held-to-maturity Securities, Unrecognized Holding Loss 4,056   0
Held-to-Maturity Securities, Fair Value      
Held-to-maturity Securities, Debt Maturities, Fair Value 1,469,229   1,217,223
Investments 3,473,841   2,952,155
Gross Unrealized Gains on Investments 23,610   47,897
Gross Unrealized Losses on Investments (5,554)   (1,124)
Investments, Fair Value Disclosure 3,491,897   2,998,928
Available-for-sale securities sold 43,199 3,500  
Obligations of U.S. Government [Member]
     
Available-for-Sale Securities, Yield      
1 to 5 years 0.00%   0.00%
Held-to-Maturity Securities, Amortized Cost      
5 to 10 years 0   0
Held-to-Maturity Securities, Gross Unrealized Gains      
1 to 5 years 0   0
Held-to-Maturity Securities, Gross Unrealized Losses      
1 to 5 years 0   0
Held-to-Maturity Securities, Fair Value      
1 to 5 years 0   0
Mortgage-backed Securities, Agency Pass-Through Certificates [Member]
     
Available-for-Sale Securities, Yield      
Agency pass-through certificates 3.04%   3.10%
Held-to-Maturity Securities, Amortized Cost      
Agency pass-through certificates 1,469,983   1,190,692
Held-to-Maturity Securities, Gross Unrealized Gains      
Agency pass-through certificates 3,302   25,729
Held-to-Maturity Securities, Gross Unrealized Losses      
Agency pass-through certificates (4,056)   0
Held-to-Maturity Securities, Fair Value      
Agency pass-through certificates 1,469,229   1,216,421
Municipal Bonds [Member]
     
Available-for-Sale Securities, Gross Unrealized Gains (Losses)      
Within 1 year 0   7
Within 1 year 0   0
Available-for-Sale Securities, Yield      
Within 1 year 0.00%   5.80%
1 to 5 years 0.00%   0.00%
5 to 10 years 0.00%   0.00%
Over 10 years 0.00%   0.00%
Held-to-Maturity Securities, Amortized Cost      
Within 1 year 0   795
5 to 10 years 0   0
5 to 10 years 0   0
Over 10 years 0   0
Held-to-Maturity Securities, Gross Unrealized Gains      
1 to 5 years 0   0
5 to 10 years 0   0
Over 10 years 0   0
Held-to-Maturity Securities, Gross Unrealized Losses      
1 to 5 years 0   0
5 to 10 years 0   0
Over 10 years 0   0
Held-to-Maturity Securities, Fair Value      
Within 1 year 0   802
1 to 5 years 0   0
5 to 10 years 0   0
Over 10 years 0   0
Municipal Bonds [Member]
     
Available-for-Sale Securities, Amortized Cost      
Over 10 years 20,430   20,442
Available-for-Sale Securities, Gross Unrealized Gains (Losses)      
Over 10 years 4,373   4,402
Over 10 years 0   0
Available-for-Sale Securities, Fair Value      
Over 10 years 24,803   24,844
Available-for-Sale Securities, Yield      
Over 10 years 6.45%   6.45%
Obligations of U.S. Government [Member]
     
Available-for-Sale Securities, Amortized Cost      
Within 1 year 16,952   19,999
1 to 5 years 58,000   0
5 to 10 years 83,300   59,300
Over 10 years 327,404   100,000
Available-for-Sale Securities, Gross Unrealized Gains (Losses)      
Within 1 year 31   42
1 to 5 years 2,576   0
5 to 10 years 1,664   4,225
Over 10 years 156   0
Within 1 year (29)   (6)
1 to 5 years 0   0
5 to 10 years 0   0
Over 10 years 0   0
Available-for-Sale Securities, Fair Value      
Within 1 year 16,954   20,035
1 to 5 years 60,576   0
5 to 10 years 84,964   63,525
Over 10 years 327,560   100,000
Available-for-Sale Securities, Yield      
Within 1 year 0.45%   0.57%
1 to 5 years 1.55%   0.00%
5 to 10 years 1.36%   2.21%
Over 10 years 0.90%   1.05%
Corporate Debt Securities [Member]
     
Available-for-Sale Securities, Amortized Cost      
Within 1 year 19,500    
1 to 5 years 317,044   336,340
5 to 10 years 62,962   62,919
Available-for-Sale Securities, Gross Unrealized Gains (Losses)      
Within 1 year 11    
1 to 5 years 4,078   2,810
5 to 10 years 998   1,324
Within 1 year 0    
1 to 5 years 0   (61)
5 to 10 years (481)   (7)
Available-for-Sale Securities, Fair Value      
Within 1 year 19,511    
1 to 5 years 321,122   339,089
5 to 10 years 63,479   64,236
Available-for-Sale Securities, Yield      
Within 1 year 0.49%    
1 to 5 years 0.84%   0.91%
5 to 10 years 2.02%   2.73%
Mortgage-backed Securities, Agency Pass-Through Certificates [Member]
     
Available-for-Sale Securities, Amortized Cost      
Agency pass-through certificates 1,098,266   1,161,668
Available-for-Sale Securities, Gross Unrealized Gains (Losses)      
Agency pass-through certificates 6,421   9,358
Agency pass-through certificates (988)   (1,050)
Available-for-Sale Securities, Fair Value      
Agency pass-through certificates $ 1,103,699   $ 1,169,976
Available-for-Sale Securities, Yield      
Agency pass-through certificates 1.99%   2.28%