Schedule I - Condensed Financial Information of AMERCO (Statements of Operations) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Revenues:
Net interest income from subs	$ 3,421,767	$ 3,275,468	$ 3,074,531
Expenses:
Operating expenses	1,568,083	1,470,047	1,479,409
Total costs and expenses	2,679,504	2,408,842	2,411,507
Equity in earnings of subsidiaries
Pretax earnings	628,358	768,911	561,418
Income tax expense	(229,934)	(279,910)	(204,677)
Earnings available to common shareholders	$ 398,424	$ 489,001	$ 356,741
Basic and diluted earnings per common share	$ 20.34	$ 24.95	$ 18.21
Weighted average common shares outstanding: basic and diluted	19,586,606	19,596,110	19,586,633
Amerco [Member]
Revenues:
Net interest income from subs	$ 1,912	$ 2,420	$ 4,862
Expenses:
Operating expenses	7,115	7,525	7,055
Other expenses	109	111	99
Total costs and expenses	7,224	7,636	7,154
Equity in earnings of subsidiaries	327,773	417,087	300,566
Interest income	103,211	93,873	75,241
Pretax earnings	425,672	505,744	373,515
Income tax expense	(27,248)	(16,743)	(16,774)
Earnings available to common shareholders	$ 398,424	$ 489,001	$ 356,741
Basic and diluted earnings per common share	$ 20.34	$ 24.95	$ 18.21
Weighted average common shares outstanding: basic and diluted	19,586,606	19,596,110	19,586,633