Leases (Components of our right-of-use assets) (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Mar. 31, 2021
Finance Lease [Abstract]
Buildings and Improvements	$ 136,568	$ 132,901
Furniture and equipment	18,316	22,316
Rental trailers and other rental equipment	182,741	203,594
Rental trucks	1,325,624	1,494,098
Right-of-use assets, gross	1,663,249	1,852,909
Less: Accumulated depreciation	(825,022)	(883,366)
Right of use assets, net	838,227	969,543
Finance Lease [Member]
Finance Lease [Abstract]
Buildings and Improvements	0	0
Furniture and equipment	18,316	22,316
Rental trailers and other rental equipment	182,741	203,594
Rental trucks	1,325,624	1,494,098
Right-of-use assets, gross	1,526,681	1,720,008
Less: Accumulated depreciation	(773,691)	(842,970)
Right of use assets, net	752,990	877,038
Operating Lease [Member]
Finance Lease [Abstract]
Buildings and Improvements	136,568	132,901
Furniture and equipment	0	0
Rental trailers and other rental equipment	0	0
Rental trucks	0	0
Right-of-use assets, gross	136,568	132,901
Less: Accumulated depreciation	(51,331)	(40,396)
Right of use assets, net	$ 85,237	$ 92,505