Schedule I - Condensed Financial Information of U-Haul Holding Company (Statements of Cash Flow) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2021
Cash flow from operating activities:
Net earnings	$ 922,998	$ 1,123,286	$ 610,856
Earnings from consolidated subsidiaries	0	0	0
Adjustments to reconcile net earnings to cash provided by operations:
Depreciation	733,879	696,955	664,001
Net loss on sales of investments	8,300	(11,872)	(10,058)
Deferred income taxes	131,754	101,091	68,411
Net change in other operating assets and liabilities:
Reinsurance recoverables and trade receivables	44,714	(9,187)	(39,516)
Prepaid expenses	(5,575)	232,342	94,359
Other assets	16,027	15,349	44,251
Related party assets	(544)	(10,357)	(487)
Accounts payable and accrued expenses	34,263	10,514	78,718
Net cash provided by operating activities	1,729,610	1,946,235	1,535,395
Cash flow from investing activities:
Purchases of property, plant and equipment	(2,723,901)	(2,136,537)	(1,441,475)
Net cash used by investing activities	(2,421,385)	(1,867,176)	(1,129,529)
Cash flow from financing activities:
Borrowings from credit facilities	1,017,898	1,969,474	922,008
Principal repayments on credit facilities	(801,994)	(437,506)	(662,588)
Debt issuance costs	(5,237)	(13,156)	(5,793)
Voting Common stock dividends paid	(19,608)	(29,412)	(49,019)
Net contribution from (to) related party			0
Net Cash Provided by (Used in) Financing Activities	59,795	1,433,155	287,353
Effects of exchange rate on cash	(11,633)	(2,089)	6,441
Increase (decrease) cash and cash equivalents	(643,613)	1,510,125	699,660
Cash and cash equivalents at beginning of period	2,704,137	1,194,012	494,352
Cash and cash equivalents at the end of period	2,060,524	2,704,137	1,194,012
U-Haul Holding Company [Member]
Cash flow from operating activities:
Net earnings	922,998	1,123,286	610,856
Earnings from consolidated subsidiaries	(581,043)	(1,011,841)	(508,632)
Adjustments to reconcile net earnings to cash provided by operations:
Depreciation	3	1	1
Net loss on sales of investments	859	292	924
Deferred income taxes	137,159	106,869	72,407
Net change in other operating assets and liabilities:
Prepaid expenses	6,120	234,490	88,898
Other assets	(2,884)	(4)	0
Related party assets	(120)	(240)	(12,000)
Accounts payable and accrued expenses	(2,499)	5,461	(4,019)
Net cash provided by operating activities	480,593	458,314	248,435
Cash flow from investing activities:
Purchases of property, plant and equipment	(1)	(11)	(3)
Net cash used by investing activities	(225,000)	(11)	(3)
Cash flow from financing activities:
Borrowings from credit facilities	0	1,200,000	200,000
Principal repayments on credit facilities	0	0	(200,000)
Debt issuance costs	0	(8,468)	(924)
Proceeds from (repayments) of intercompany loans	(637,585)	(284,438)	211,064
Voting Common stock dividends paid	(19,608)	(29,412)	(49,019)
Net contribution from (to) related party	0	0	41,199
Net Cash Provided by (Used in) Financing Activities	(671,310)	877,682	202,320
Effects of exchange rate on cash	(6,940)	(1,591)	5,773
Increase (decrease) cash and cash equivalents	(422,657)	1,334,394	456,525
Cash and cash equivalents at beginning of period	2,085,447	751,053	294,528
Cash and cash equivalents at the end of period	$ 1,662,790	$ 2,085,447	$ 751,053