Borrowings (Table Text Block)	3 Months Ended	6 Months Ended
	Sep. 30, 2020	Sep. 30, 2020
Debt Instruments [Abstract]
Long-Term Debt		September 30,   March 31,   2020 Rates (a)     Maturities   2020   2020                 (Unaudited)                     (In thousands) Real estate loan (amortizing term)       1.66 %       2023 $ 87,913 $ 92,913 Senior mortgages 3.11 % - 6.62 %   2021 - 2038   2,098,659   2,029,878 Real estate loans (revolving credit) 1.56 % - 3.25 %   2022 - 2025   535,000   519,000 Fleet loans (amortizing term) 2.04 % - 4.66 %   2020 - 2027   184,861   224,089 Fleet loans (revolving credit) 1.31 % - 2.36 %   2022 - 2024   510,000   567,000 Finance/capital leases (rental equipment) 1.92 % - 5.04 %   2020 - 2026   612,150   734,870 Finance liability (rental equipment) 1.60 % - 4.22 %   2020 - 2028   528,702   398,834 Other obligations 2.50 % - 8.00 %   2020 - 2049   174,483   84,484 Notes, loans and finance/capital leases payable                   4,731,768   4,651,068 Less: Debt issuance costs                     (30,543)   (29,777) Total notes, loans and finance/capital leases payable, net         $ 4,701,225 $ 4,621,291                             (a) Interest rates as of September 30, 2020, including the effect of applicable hedging instruments.
Annual Maturities of Notes, Loans and Leases Payable		Year Ended September 30,     2021   2022   2023   2024   2025   Thereafter     (Unaudited)     (In thousands) Notes, loans and finance/capital leases payable, secured $ 575,971 $ 840,903 $ 703,945 $ 780,395 $ 264,733 $ 1,565,821
Components of interest expense	Quarter Ended September 30,     2020   2019     (Unaudited)     (In thousands) Interest expense $ 41,600 $ 44,743 Capitalized interest   (3,494)   (6,669) Amortization of transaction costs   1,458   1,047 Interest expense resulting from cash flow hedges   961   1 Total interest expense $ 40,525 $ 39,122	Six Months Ended September 30,     2020   2019     (Unaudited)     (In thousands) Interest expense $ 83,511 $ 88,074 Capitalized interest   (7,928)   (12,168) Amortization of transaction costs   2,755   2,100 Interest expense resulting from cash flow hedges   1,708   4 Total interest expense $ 80,046 $ 78,010
Interest rates and company borrowings	Revolving Credit Activity       Quarter Ended September 30,       2020   2019       (Unaudited)       (In thousands, except interest rates)   Weighted average interest rate during the quarter   1.67 % 3.50 % Interest rate at the end of the quarter   1.67 % 3.36 % Maximum amount outstanding during the quarter $ 1,105,000 $ 1,015,000   Average amount outstanding during the quarter $ 1,059,130 $ 1,004,348   Facility fees $ 90 $ 45	Revolving Credit Activity       Six Months Ended September 30,       2020   2019       (Unaudited)       (In thousands, except interest rates)   Weighted average interest rate during the period   1.67 % 3.61 % Interest rate at the end of the period   1.67 % 3.36 % Maximum amount outstanding during the period $ 1,175,000 $ 1,015,000   Average amount outstanding during the period $ 1,109,978 $ 985,954   Facility fees $ 94 $ 107