Schedule II - AMERCO and Consolidated Subsidiaries, Valuation and Qualifying Accounts (Details) - Amerco [Member] - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Allowance for doubtful accounts (deducted from trade receivable) [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	$ 535	$ 549	$ 496
Additions charged to cost and expenses	2,179	731	1,550
Additions charged to other accounts	2,680	0	0
Deductions	(973)	(745)	(1,497)
Balance at year end	4,421	535	549
Allowance for obsolescence (deducted from inventory) [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	3,063	2,322	5,329
Additions charged to cost and expenses	0	741	0
Additions charged to other accounts	0	0	0
Deductions	(1,647)	0	(3,007)
Balance at year end	1,416	3,063	2,322
Allowance for LIFO (deducted from inventory) [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	18,886	18,987	16,126
Additions charged to cost and expenses	2,946	0	2,861
Additions charged to other accounts	0	0	0
Deductions	0	(101)	0
Balance at year end	21,832	18,886	18,987
Allowance for probable losses (deducted from mortgage loans) [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	493	493	618
Additions charged to cost and expenses	0	0	0
Additions charged to other accounts	0	0	0
Deductions	(45)	0	(125)
Balance at year end	$ 448	$ 493	$ 493