Leases (Table Text Block)	3 Months Ended
	Jun. 30, 2021
Leases [Abstract]
Supplemental Balance Sheet Information Related to Leases	As of June 30, 2021     Finance   Operating   Total     (Unaudited)     (In thousands) Buildings and improvements $ – $ 135,174 $ 135,174 Furniture and equipment   22,176   –   22,176 Rental trailers and other rental equipment   197,981   –   197,981 Rental trucks   1,395,144   –   1,395,144 Right-of-use assets, gross   1,615,301   135,174   1,750,475 Less: Accumulated depreciation   (800,426)   (45,805)   (846,231) Right-of-use assets, net $ 814,875 $ 89,369 $ 904,244       As of March 31, 2021     Finance   Operating   Total     (In thousands) Buildings and improvements $ – $ 132,901 $ 132,901 Furniture and equipment   22,316   –   22,316 Rental trailers and other rental equipment   203,594   –   203,594 Rental trucks   1,494,098   –   1,494,098 Right-of-use assets, gross   1,720,008   132,901   1,852,909 Less: Accumulated depreciation   (842,970)   (40,396)   (883,366) Right-of-use assets, net$ 877,038 $ 92,505 $ 969,543
Summary of Weighted-average remaining lease terms and Discount rates	Finance leases       June 30,   March 31,       2021   2021               Weighted average remaining lease term (years)   3   3   Weighted average discount rate   3.6 % 3.6 %       Operating leases       June 30,   March 31,       2021   2021               Weighted average remaining lease term (years)   14.8   14.7   Weighted average discount rate  4.6 % 4.6 %
Components of Lease Expense	Three Months Ended     June 30, 2021   June 30, 2020     (Unaudited)     (In thousands)           Operating lease costs $ 8,077 $ 7,137           Finance lease cost:         Amortization of right-of-use assets $ 183,277 $ 40,836 Interest on lease liabilities   4,571   6,282 Total finance lease cost$ 187,848 $ 47,118
Maturities of Lease Liabilities	Finance leases   Operating leases     (Unaudited) Years ending June 30,   (In thousands)           2022 $ 168,277 $ 24,926 2023   132,482   22,560 2024   98,586   21,418 2025   68,555   6,414 2026   35,679   3,560 Thereafter   –   61,302 Total lease payments   503,579   140,180 Less: imputed interest   (35,095)   (50,790) Present value of lease liabilities$ 468,484 $ 89,390