Investments - Unrealized Losses (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Cost or amortized Cost
Total Cost or Amortized Cost	$ 2,624,991	$ 795,067
Fair value
Total Fair Value	2,323,283	778,176
Unrealized Loss
Total Unrealized Loss	$ (301,708)	$ (16,891)
Percent to Total	100.00%
NAIC Rating 1 | AAA/AA/A | Aaa/Aa/A
Cost or amortized Cost
Total Cost or Amortized Cost	$ 2,084,118
Fair value
Total Fair Value	1,840,726
Unrealized Loss
Total Unrealized Loss	$ (243,392)
Percent to Total	80.70%
NAIC Rating 2 | BBB | Baa
Cost or amortized Cost
Total Cost or Amortized Cost	$ 399,832
Fair value
Total Fair Value	353,124
Unrealized Loss
Total Unrealized Loss	$ (46,708)
Percent to Total	15.50%
NAIC Rating 3 | BB | Ba
Cost or amortized Cost
Total Cost or Amortized Cost	$ 75,146
Fair value
Total Fair Value	67,738
Unrealized Loss
Total Unrealized Loss	$ (7,408)
Percent to Total	2.50%
NAIC Rating 4 | B | B
Cost or amortized Cost
Total Cost or Amortized Cost	$ 65,238
Fair value
Total Fair Value	61,152
Unrealized Loss
Total Unrealized Loss	$ (4,086)
Percent to Total	1.30%
NAIC Rating 5 | CCC | Caa
Cost or amortized Cost
Total Cost or Amortized Cost	$ 657
Fair value
Total Fair Value	543
Unrealized Loss
Total Unrealized Loss	$ (114)
Percent to Total	0.00%
NAIC Six Rating Member | Standard Poors CC Or Lower Member | Ca
Unrealized Loss
Percent to Total	0.00%