Schedule I - Condensed Financial Information of AMERCO (Statements of Operations) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Revenues:
Net interest income from subs	$ 3,768,707	$ 3,601,114	$ 3,421,767
Expenses:
Operating expenses	1,981,180	1,807,056	1,567,181
Total costs and expenses	3,147,720	2,835,868	2,678,602
Equity in earnings of subsidiaries
Pretax earnings	477,529	637,613	628,358
Income tax expense	(106,672)	152,970	(229,934)
Earnings available to common shareholders	$ 370,857	$ 790,583	$ 398,424
Basic and diluted earnings per common share	$ 18.93	$ 40.36	$ 20.34
Weighted average common shares outstanding: basic and diluted	19,592,048	19,588,889	19,586,606
Amerco [Member]
Revenues:
Net interest income from subs	$ 8,601	$ 4,606	$ 1,912
Expenses:
Operating expenses	8,840	7,003	7,115
Other expenses	93	91	109
Total costs and expenses	8,933	7,094	7,224
Equity in earnings of subsidiaries	279,589	681,786	327,773
Interest income	112,649	120,549	103,211
Pretax earnings	391,906	799,847	425,672
Income tax expense	(21,049)	(9,264)	(27,248)
Earnings available to common shareholders	$ 370,857	$ 790,583	$ 398,424
Basic and diluted earnings per common share	$ 18.93	$ 40.36	$ 20.34
Weighted average common shares outstanding: basic and diluted	19,592,048	19,588,889	19,586,606