Quarterly report pursuant to Section 13 or 15(d)

Available-for-Sale Securities, at Fair Value Schedule of Unrealized Loss on Investments (Details)

v3.4.0.3
Available-for-Sale Securities, at Fair Value Schedule of Unrealized Loss on Investments (Details)
$ in Thousands
Mar. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Schedule of Available-for-sale Securities [Line Items]    
Available-for-Sale Securities, Number of Positions 1,147 1,181
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Less than One Year 65 121
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year 190 182
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value $ 513,067 $ 1,503,939
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses (20,746) (26,984)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value 1,240,930 1,141,839
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses (28,167) (44,412)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value 1,753,997 2,645,778
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses $ (48,913) $ (71,396)