Quarterly report pursuant to Section 13 or 15(d)

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

v3.19.1
Available-for-Sale Securities, at Fair Value Schedule of Unrealized Loss on Investments (Details)
$ in Thousands
Mar. 31, 2019
USD ($)
position
Dec. 31, 2018
USD ($)
position
Debt Securities, Available-for-sale [Abstract]    
Debt Securities, Available-for-sale, Number of Positions | position 1,442 1,550
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Number of Positions | position 100 290
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions | position 452 489
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months $ 1,010,182 $ 4,386,946
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss (27,532) (66,520)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer 6,937,554 9,501,123
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss (154,153) (370,082)
Debt Securities, Available-for-sale, Unrealized Loss Position 7,947,736 13,888,069
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss $ (181,685) $ (436,602)