Schedule I - Condensed Financial Information of AMERCO (Statements of Operations) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Revenues:
Net interest income from subs	$ 3,978,868	$ 3,768,707	$ 3,601,114
Expenses:
Operating expenses	2,117,148	1,981,180	1,807,056
Total costs and expenses	3,438,740	3,147,720	2,835,868
Equity in earnings of subsidiaries	0	0	0
Pretax earnings	378,124	477,529	637,613
Earnings available to common shareholders	$ 442,048	$ 370,857	$ 790,583
Basic and diluted earnings per common share	$ 22.55	$ 18.93	$ 40.36
Weighted average common shares outstanding: basic and diluted	19,603,708	19,592,048	19,588,889
Amerco [Member]
Revenues:
Net interest income from subs	$ 6,586	$ 8,601	$ 4,606
Expenses:
Operating expenses	10,622	8,840	7,003
Other expenses	96	93	91
Total costs and expenses	10,718	8,933	7,094
Equity in earnings of subsidiaries	205,940	279,589	681,786
Interest income	130,670	112,649	120,549
Pretax earnings	332,478	391,906	799,847
Income tax expense	109,570	(21,049)	(9,264)
Earnings available to common shareholders	$ 442,048	$ 370,857	$ 790,583
Basic and diluted earnings per common share	$ 22.55	$ 18.93	$ 40.36
Weighted average common shares outstanding: basic and diluted	19,603,708	19,592,048	19,588,889