Schedule I - Condensed Financial Information Of AMERCO (Statements of Comprehensive Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Net earnings	$ 610,856	$ 442,048	$ 370,857
Amerco [Member]
Net earnings	610,856	442,048	370,857
Other comprehensive income (loss)	72,205	101,350	(62,075)
Total comprehensive income	$ 683,061	$ 543,398	$ 308,782