Condensed Consolidated Balance Sheets Parenthetical (USD $)	Dec. 31, 2014	Mar. 31, 2014
Series Preferred Stock With or Without Par Value [Member]
Preferred stock:
Preferred stock, shares authorized	50,000,000	50,000,000
Series A Preferred Stock [Member]
Preferred stock:
Preferred stock, shares authorized	6,100,000	6,100,000
Preferred stock, shares issued	6,100,000	6,100,000
Preferred stock, shares outstanding	0	0
Preferred stock, no par value	0.00	0.00
Series B Preferred Stock [Member]
Preferred stock:
Preferred stock, shares authorized	100,000	100,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Preferred stock, no par value	0.00	0.00
Series Common Stock With or Without Par Value [Member]
Common stock:
Common stock, shares authorized	150,000,000	150,000,000
Series A Common Stock [Member]
Common stock:
Common stock, shares authorized	10,000,000	10,000,000
Common stock, shares, issued	0	0
Common stock, shares, outstanding	0	0
Common stock, par or stated value per share	0.25	0.25
Common Stock [Member]
Common stock:
Common stock, shares authorized	150,000,000	150,000,000
Common stock, par or stated value per share	0.25	0.25
Amerco Common Stock [Member]
Common stock:
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares, issued	41,985,700	41,985,700
Common stock, shares, outstanding	19,607,788	19,607,788
Common stock, par or stated value per share	0.25	0.25
Common Stock in Treasury [Member]
Treasury stock:
Treasury stock, shares	22,377,912	22,377,912
Preferred Stock in Treasury [Member]
Treasury stock:
Treasury stock, shares	6,100,000	6,100,000