Condensed Financial Information of AMERCO, Statements of Operations (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Revenues:
Net interest income from subsidiaries	$ 3,074,531	$ 2,835,252	$ 2,558,587
Expenses:
Operating expenses	1,479,409	1,313,674	1,193,934
Total costs and expenses	2,411,507	2,205,038	2,059,404
Equity in earnings of subsidiaries	0	0	0
Interest Income	97,525	92,692	90,696
Pretax earnings	561,418	537,522	408,487
Income tax expense	(204,677)	(195,131)	(143,779)
Earnings available to common shareholders	356,741	342,391	264,708
Basic and diluted earnings per common share	$ 18.21	$ 17.51	$ 13.56
Weighted average common shares outstanding: basic and diluted	19,586,633	19,558,758	19,518,779
AMERCO [Member]
Revenues:
Net interest income from subsidiaries	4,862	6,465	5,329
Expenses:
Operating expenses	7,055	6,636	13,611
Other expenses	99	97	97
Total costs and expenses	7,154	6,733	13,708
Equity in earnings of subsidiaries	300,566	287,803	212,164
Interest Income	75,241	86,916	91,125
Pretax earnings	373,515	374,451	294,910
Income tax expense	(16,774)	(32,060)	(30,202)
Earnings available to common shareholders	$ 356,741	$ 342,391	$ 264,708
Basic and diluted earnings per common share	$ 18.21	$ 17.51	$ 13.56
Weighted average common shares outstanding: basic and diluted	19,586,633	19,558,758	19,518,779