Employee Benefit Plans - Employee Incentive Programs (Details) - USD ($)	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Profit Sharing Plan
Employee incentive programs
Employer contribution under plan	$ 0	$ 0	$ 0
401 (k) Plan
Employee incentive programs
Employer matching contribution (as a percent)	50.00%
Vesting period of employer matching contributions	1 month
Employer contribution under plan	$ 1,400,000	$ 1,300,000	$ 1,200,000