Line of Credit - Additional Information (Details)	12 Months Ended
	Mar. 31, 2021 USD ($)	Mar. 31, 2020 USD ($)	Mar. 31, 2019 USD ($)	Mar. 12, 2021 USD ($)	Mar. 29, 2018 USD ($)
Line Of Credit Facility [Line Items]
Minimum interest coverage ratio	3.50
Line of credit	$ 0	$ 129,000,000
Remaining borrowing capacity	300,000,000	$ 171,000,000
Line of credit facility, interest rate at period end		2.30%
Interest expense	$ 2,541,000	$ 1,274,000	$ 2,055,000
Debt, weighted average interest rate	2.20%	2.40%	3.70%
Additional unamortized debt issuance costs	$ 1,423,000
Debt issuance costs written off	326,000
Amortization of deferred debt issuance costs, including written off	1,026,000	$ 710,000	$ 710,000
Other Assets
Line Of Credit Facility [Line Items]
Debt issuance costs	$ 2,521,000	$ 2,124,000	$ 2,124,000
Maximum | Fiscal Quarter Ending on or Prior to September 30, 2016
Line Of Credit Facility [Line Items]
Leverage ratio	3.75
Revolving Credit Facility
Line Of Credit Facility [Line Items]
Maximum borrowing capacity	$ 150,000,000			$ 300,000,000	$ 300,000,000
Credit agreement maturity date	Mar. 12, 2026
Debt instrument, basis spread on variable rate	1.00%
Revolving Credit Facility | Minimum
Line Of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate	0.50%
Line of credit facility, unused capacity, commitment fee percentage	0.25%
Revolving Credit Facility | Maximum
Line Of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate	1.75%
Line of credit facility, unused capacity, commitment fee percentage	0.45%
Revolving Credit Facility | Federal Funds Effective Rate
Line Of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate	0.50%
Revolving Credit Facility | London Interbank Offered Rate ("LIBOR")
Line Of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate	1.00%
Revolving Credit Facility | London Interbank Offered Rate (LIBOR) | Minimum
Line Of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate	1.50%
Revolving Credit Facility | London Interbank Offered Rate (LIBOR) | Maximum
Line Of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate	2.75%
Letter of Credit
Line Of Credit Facility [Line Items]
Maximum borrowing capacity				10,000,000
Swing-Line Loans
Line Of Credit Facility [Line Items]
Maximum borrowing capacity				$ 10,000,000