Related Party Transactions (Narratives) (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2021
Related party notes receivable:
One time cash interest proceeds	$ 4.0
Property Management Fee [Abstract]
Management fees received exclusive of reimbursed expenses	$ 37.0	$ 38.5	$ 31.2
Minimum [Member]
Property Management Fee [Abstract]
Management fee rate	4.00%
Maximum [Member]
Property Management Fee [Abstract]
Management fee rate	10.00%
Sac Holdings [Member]
Related party costs and expenses:
Revenue, excluding dealer agreement commissions and expenses	$ 29.8	28.5	25.5
Sac Holdings, Mercury, Four Sac, Five Sac, Galaxy and Private Mini [Member]
Related party costs and expenses:
Expenses, related parties	2.4	2.4	2.6
Cash flow, related party	27.4	25.9	22.6
Revenue, generated by the dealer agreement from related parties	418.9	417.9	323.8
Commission expenses, generated from dealer agreement with related parties	$ 88.1	$ 88.3	$ 69.2