Income Taxes - Reconciliation Between U.S. Federal Statutory Tax Rate and Effective Tax Rate (Details)	12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2020
Reconciliation Between U.S. Federal Statutory Tax Rate and Effective Tax Rate
Provision for income taxes at U.S. federal statutory tax rate	21.00%	21.00%	21.00%
State and local taxes (net of federal tax benefit)	3.70%	3.90%	4.00%
Effect of state tax law changes	0.30%	(0.20%)	(3.90%)
Federal tax credits	(1.00%)	(0.50%)	(3.70%)
Tax rate differential from tax loss carryback	0.00%	0.00%	(5.60%)
Adjustment for prior year provision to return differences	(0.30%)	(0.20%)	(1.00%)
Other, net	0.00%	(0.10%)	0.00%
Effective tax rate	23.70%	23.90%	10.80%