Investments - Unrealized Losses (Details) - Debt Securities - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Cost or amortized Cost
Total Cost or Amortized Cost	$ 473,644	$ 185,731
Fair value
Total Fair Value	458,606	183,177
Unrealized Loss
Total Unrealized Loss	$ (15,038)	$ (2,554)
Percent to Total	100.00%
NAIC Rating 1 | AAA/AA/A | Aaa/Aa/A
Cost or amortized Cost
Total Cost or Amortized Cost	$ 365,229
Fair value
Total Fair Value	352,591
Unrealized Loss
Total Unrealized Loss	$ (12,638)
Percent to Total	84.10%
NAIC Rating 2 | BBB | Baa
Cost or amortized Cost
Total Cost or Amortized Cost	$ 55,575
Fair value
Total Fair Value	54,161
Unrealized Loss
Total Unrealized Loss	$ (1,414)
Percent to Total	9.40%
NAIC Rating 3 | BB | Ba
Cost or amortized Cost
Total Cost or Amortized Cost	$ 23,838
Fair value
Total Fair Value	23,455
Unrealized Loss
Total Unrealized Loss	$ (383)
Percent to Total	2.50%
NAIC Rating 4 | B | B
Cost or amortized Cost
Total Cost or Amortized Cost	$ 26,201
Fair value
Total Fair Value	25,616
Unrealized Loss
Total Unrealized Loss	$ (585)
Percent to Total	3.90%
NAIC Rating 5 | CCC | Caa
Cost or amortized Cost
Total Cost or Amortized Cost	$ 2,801
Fair value
Total Fair Value	2,783
Unrealized Loss
Total Unrealized Loss	$ (18)
Percent to Total	0.10%
NAIC Six Rating Member | Standard Poors CC Or Lower Member | Ca
Unrealized Loss
Percent to Total	0.00%