Schedule V - AMERCO and Consolidated Subsidiaries, Supplemental Information (for Property-Casualty Insurance Operations) (Details) - Property Casualty Insurance Operations [Member] - Amerco [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Supplemental Information For Property And Casualty Insurance Underwriters [Abstract]
Deferred policy acquisition costs	$ 0	$ 0	$ 0
Reserves for unpaid claims and claims adjustment expense	159,162	177,963	209,127
Discount if any, deducted	0	0	0
Unearned premiums	334	(294)	233
Net earned premiums (1)	89,667	70,285	69,141
Net investment income (2)	24,385	16,335	19,926
Claim and claim adjustment expenses incurred related to current year	28,980	20,670	22,137
Prior years	(6,290)	(3,865)	(9,535)
Amortization of deferred policy acquisition costs	0	0	0
Paid claims and claim adjustment expense	24,012	25,759	24,608
Net premiums written (1)	$ 90,002	$ 69,989	$ 66,277