Investments - Summary of the Total Value of Fixed Income Securities (Details) - USD ($) $ in Thousands		Sep. 30, 2020	Dec. 31, 2019
U.S. government
Fair value
Less than 12 months		$ 5,900	$ 2,505
12 months and greater			8,463
Total Fair Value		5,900	10,968
Cost or amortized Cost
Amortized cost, less than 12 months		5,936	2,506
12 months and greater			8,494
Total Cost or Amortized Cost		5,936	11,000
Unrealized loss
Less than 12 months		(36)	(1)
12 months and greater			(31)
Total Unrealized Loss		(36)	(32)
U.S. Agency
Fair value
Less than 12 months			6,794
Total Fair Value			6,794
Cost or amortized Cost
Amortized cost, less than 12 months			6,836
Total Cost or Amortized Cost			6,836
Unrealized loss
Less than 12 months			(42)
Total Unrealized Loss			(42)
Agency MBS
Fair value
Less than 12 months		45,929	21,548
12 months and greater		244	41,718
Total Fair Value		46,173	63,266
Cost or amortized Cost
Amortized cost, less than 12 months		46,229	21,664
12 months and greater		245	42,165
Total Cost or Amortized Cost		46,474	63,829
Unrealized loss
Less than 12 months		(300)	(116)
12 months and greater		(1)	(447)
Total Unrealized Loss		(301)	(563)
ABS/CMBS
Fair value
Less than 12 months	[1]	35,837	74,968
12 months and greater	[1]	14,586	18,036
Total Fair Value	[1]	50,423	93,004
Cost or amortized Cost
Amortized cost, less than 12 months	[1]	36,236	75,332
12 months and greater	[1]	14,744	18,148
Total Cost or Amortized Cost	[1]	50,980	93,480
Unrealized loss
Less than 12 months	[1]	(399)	(364)
12 months and greater	[1]	(158)	(112)
Total Unrealized Loss	[1]	(557)	(476)
Corporate Debt
Fair value
Less than 12 months		107,521	16,478
12 months and greater		4,669	9,348
Total Fair Value		112,190	25,826
Cost or amortized Cost
Amortized cost, less than 12 months		110,664	16,950
12 months and greater		4,957	9,694
Total Cost or Amortized Cost		115,621	26,644
Unrealized loss
Less than 12 months		(3,143)	(472)
12 months and greater		(288)	(346)
Total Unrealized Loss		(3,431)	(818)
Municipal
Fair value
Less than 12 months		32,681	47,018
Total Fair Value		32,681	47,018
Cost or amortized Cost
Amortized cost, less than 12 months		32,954	47,740
Total Cost or Amortized Cost		32,954	47,740
Unrealized loss
Less than 12 months		(273)	(722)
Total Unrealized Loss		(273)	(722)
Debt Securities
Fair value
Less than 12 months		227,868	169,311
12 months and greater		19,499	77,565
Total Fair Value		247,367	246,876
Cost or amortized Cost
Amortized cost, less than 12 months		232,019	171,028
12 months and greater		19,946	78,501
Total Cost or Amortized Cost		251,965	249,529
Unrealized loss
Less than 12 months		(4,151)	(1,717)
12 months and greater		(447)	(936)
Total Unrealized Loss		$ (4,598)	$ (2,653)

[1] Non-agency asset-backed and commercial mortgage-backed