Summary of Significant Accounting Policies - Narrative (Details) - USD ($)	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Sep. 30, 2021	Dec. 31, 2020
Summary Of Significant Accounting Policies [Line Items]
Liabilities settled	$ 0	$ 79,000
Increase (decrease) in asset retirement obligations accrual	$ 85,000	(6,000)
Wireless licenses term	10 years
Impairment charges	$ 0	0
Payments to acquire intangible assets	17,031,000	25,004,000
Indefinite-lived intangible assets, period Increase from recognition of receivables	9,100,000
Increase in deferred charges	10,900,000
Impairment of long-lived assets	0	$ 0
Lease extension			10 years	10 years
Tax benefits attributed to share-based compensation expense	$ 0
Potentially dilutive securities outstanding but excluded from computation of earnings per share	241,629	352,216
Stock Options
Summary Of Significant Accounting Policies [Line Items]
Award expiration period	10 years
Award requisite service period	3 years
Dividend yield	0.00%	0.00%
Stock Options | Grants Prior To November 2020
Summary Of Significant Accounting Policies [Line Items]
Award requisite service period	4 years
Restricted Stock
Summary Of Significant Accounting Policies [Line Items]
Award requisite service period	4 years
Dividend yield	0.00%
Minimum
Summary Of Significant Accounting Policies [Line Items]
Lease extension	3 years
Accelerated vesting provision, change in control, purchase price (in dollars per share)	$ 100
Maximum
Summary Of Significant Accounting Policies [Line Items]
Lease extension	10 years
Advertising
Summary Of Significant Accounting Policies [Line Items]
Advertising and promotional expense	$ 62,000	$ 92,000
Customer Concentration Risk | Accounts Receivable
Summary Of Significant Accounting Policies [Line Items]
Accounts receivable	0	0
Leased Premises
Summary Of Significant Accounting Policies [Line Items]
Liabilities settled	$ 0	$ 100,000