Leases (Table Text Block)	12 Months Ended
	Mar. 31, 2020
Leases [Abstract]
Supplemental Balance Sheet Information Related to Leases	As of March 31, 2020     Finance   Operating   Total     (In thousands)               Buildings and improvements $ – $ 125,547 $ 125,547 Furniture and equipment   21,113   –   21,113 Rental trailers and other rental equipment   116,072   –   116,072 Rental trucks   1,738,081   –   1,738,081 Right-of-use assets, gross   1,875,266   125,547   2,000,813 Less: Accumulated depreciation   (794,913)   (18,916)   (813,829) Right-of-use assets, net $ 1,080,353 $ 106,631 $ 1,186,984
Summary of Weighted-average remaining lease terms and Discount rates	Finance   Operating   Weighted average remaining lease term (years)   4 Years   14 Years   Weighted average discount rate   3.5 % 4.6 %
Lease costs	Twelve Months Ended     March 31, 2020     (In thousands)       Operating lease costs $ 27,494       Finance lease cost:     Amortization of right-of-use assets $ 186,860 Interest on lease liabilities   30,901 Total finance lease cost $ 217,761
Maturities of Lease Liabilities	Finance leases   Operating leases Year ending March 31,   (In thousands)           2021 $ 218,424 $ 23,782 2022   164,190   22,001 2023   124,160   21,238 2024   106,156   20,616 2025   75,502   9,701 Thereafter   46,438   64,806 Total lease payments   734,870   162,144 Less: imputed interest   –   (55,701) Present value of lease liabilities $ 734,870 $ 106,443
Schedule of future minimum lease payments	Total     (In thousands) Year-ended March 31:     2020 $ 20,852 2021   18,495 2022   16,750 2023   16,317 2024   15,736 Thereafter   54,683 Total $ 142,833