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
Mar. 31, 2013
Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]    
Available-for-Sale Securities, Number of Positions 1,660 1,493
Available-for-Sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Number of Positions 519 250
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Number of Positions 40 47
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value $ 5,372,704 $ 2,548,995
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses (79,512) (18,610)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value 60,459 52,689
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses (8,957) (9,628)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value 5,433,163 2,601,684
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses $ (88,469) $ (28,238)