Quarterly report pursuant to Section 13 or 15(d)

Schedule of Unrealized Loss on Investments (Details)

v2.4.0.6
Schedule of Unrealized Loss on Investments (Details) (USD $)
In Thousands, unless otherwise specified
Sep. 30, 2012
Dec. 31, 2011
Schedule of Available-for-sale Securities [Line Items]    
Available-for-Sale Securities, Number of Positions 1,490 854
Available-for-Sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Number of Positions 76 264
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Number of Positions 70 20
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value $ 301,709 $ 1,277,120
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses (11,682) (175,348)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value 181,019 15,608
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses (18,425) (4,113)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value 482,728 1,292,728
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses $ (30,107) $ (179,461)