Investments - Unrealized Losses (Details) - Fixed Income Securities - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Cost or amortized Cost
Total Cost or Amortized Cost	$ 1,543,009	$ 795,067
Fair value
Total Fair Value	1,445,023	778,176
Unrealized Loss
Total Unrealized Loss	$ (97,986)	$ (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	$ 1,199,156
Fair value
Total Fair Value	1,119,133
Unrealized Loss
Total Unrealized Loss	$ (80,023)
Percent to Total	81.70%
NAIC Rating 2 | BBB | Baa
Cost or amortized Cost
Total Cost or Amortized Cost	$ 232,808
Fair value
Total Fair Value	217,951
Unrealized Loss
Total Unrealized Loss	$ (14,857)
Percent to Total	15.20%
NAIC Rating 3 | BB | Ba
Cost or amortized Cost
Total Cost or Amortized Cost	$ 64,217
Fair value
Total Fair Value	62,216
Unrealized Loss
Total Unrealized Loss	$ (2,001)
Percent to Total	2.00%
NAIC Rating 4 | B | B
Cost or amortized Cost
Total Cost or Amortized Cost	$ 45,409
Fair value
Total Fair Value	44,376
Unrealized Loss
Total Unrealized Loss	$ (1,033)
Percent to Total	1.00%
NAIC Rating 5 | CCC | Caa
Cost or amortized Cost
Total Cost or Amortized Cost	$ 1,419
Fair value
Total Fair Value	1,347
Unrealized Loss
Total Unrealized Loss	$ (72)
Percent to Total	0.10%
NAIC Six Rating Member | Standard Poors CC Or Lower Member | Ca
Unrealized Loss
Percent to Total	0.00%