Rental Truck Depreciation Data (Details) (Rental trucks, USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011
Rental trucks
Schedule of rental trucks depreciation:
Salvage value percentage	15.00%
Percentage reduction for year one, depreciation	16.00%
Percentage reduction for year two, depreciation	13.00%
Percentage reduction for year three, depreciation	11.00%
Percentage reduction for year four, depreciation	9.00%
Percentage reduction for year five, depreciation	8.00%
Percentage reduction for year six, depreciation	7.00%
Percentage reduction for year seven, depreciation	6.00%
Percentage reduction if straight line approach used each year for depreciation calculation	5.70%
Increase in amount of depreciation because of accelerated method	$ 57.0	$ 54.6	$ 44.8
Month and year depreciation method changed	2012-10
Salvage value percentage under the old declining balance method	20.00%