Underwriting Information - Gross Written Premiums by State (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Gross written premiums
Amount	$ 83,807	$ 58,346	$ 155,301	$ 112,377
% of GWP	100.00%	100.00%	100.00%	100.00%
California
Gross written premiums
Amount	$ 38,420	$ 32,306	$ 71,172	$ 62,754
% of GWP	45.90%	55.40%	45.80%	55.80%
Texas
Gross written premiums
Amount	$ 18,796	$ 11,000	$ 34,587	$ 21,439
% of GWP	22.40%	18.80%	22.30%	19.10%
Hawaii
Gross written premiums
Amount	$ 3,840	$ 2,921	$ 6,892	$ 5,013
% of GWP	4.60%	5.00%	4.50%	4.50%
Washington
Gross written premiums
Amount	$ 3,055	$ 1,926	$ 5,661	$ 3,520
% of GWP	3.70%	3.30%	3.60%	3.10%
South Carolina
Gross written premiums
Amount	$ 2,704	$ 1,686	$ 5,114	$ 3,355
% of GWP	3.20%	2.90%	3.30%	3.00%
North Carolina
Gross written premiums
Amount	$ 2,609	$ 947	$ 4,293	$ 1,687
% of GWP	3.10%	1.60%	2.80%	1.50%
Oregon
Gross written premiums
Amount	$ 2,289	$ 1,671	$ 4,386	$ 3,126
% of GWP	2.70%	2.90%	2.80%	2.80%
Mississippi
Gross written premiums
Amount	$ 2,034	$ 1,222	$ 3,455	$ 2,068
% of GWP	2.40%	2.10%	2.20%	1.80%
Other
Gross written premiums
Amount	$ 10,060	$ 4,667	$ 19,741	$ 9,415
% of GWP	12.00%	8.00%	12.70%	8.40%