Description of Business and Summary of Significant Accounting Policies - Effects of Reinsurance on Premium Written and Earned (Details) $ in Thousands	6 Months Ended
	Sep. 30, 2021 USD ($)
Description of Business and Summary of Significant Accounting Policies
Direct premiums, written	$ 177,333
Ceded premiums, written	(158,793)
Net premiums, written	18,540
Direct premiums, earned	134,712
Ceded premiums, earned	(126,743)
Net premiums, earned	$ 7,969