Condensed Consolidated Balance Sheets Parenthetical	Mar. 31, 2021 $ / shares shares
Series Preferred Stock With or Without Par Value Authorized [Member]
Preferred stock:
Preferred stock, shares authorized	50,000,000
Series A Preferred Stock [Member]
Preferred stock:
Preferred stock, shares authorized	6,100,000
Preferred stock, shares issued	6,100,000
Series B Preferred Stock [Member]
Preferred stock:
Preferred stock, shares authorized	100,000
Series Common Stock With or Without Par Value Authorized [Member]
Preferred stock:
Preferred stock, shares authorized	250,000,000
Serial Common Stock [Member]
Common stock:
Common stock, shares authorized	10,000,000
Common stock, par or stated value per share | $ / shares	$ 0.25
Common Stock [Member]
Common stock:
Common stock, shares authorized	250,000,000
Common stock, par or stated value per share | $ / shares	$ 0.25
Amerco Common Stock [Member]
Common stock:
Common stock, shares authorized	250,000,000
Common stock, shares, issued	41,985,700
Common stock, shares, outstanding	19,607,788
Common stock, par or stated value per share | $ / shares	$ 0.25
Common Stock in Treasury [Member]
Treasury stock:
Treasury stock, shares	22,377,912
Preferred Stock in Treasury [Member]
Treasury stock:
Treasury stock, shares	6,100,000