Schedule I - Condensed Financial Information of U-Haul Holding Company (Statements of Cash Flow) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Cash flow from operating activities:
Net Income (Loss)	$ 628,707	$ 924,472	$ 1,124,362
Adjustments to reconcile net earnings to cash provided by operations:
Depreciation	817,889	733,879	696,955
Amortization of debt issuance costs	6,712	7,087	5,659
Deferred income taxes, net	98,379	131,754	101,091
Net change in other operating assets and liabilities:
Prepaid expenses	(4,451)	(5,575)	(232,342)
Other assets	(9,889)	(6,405)	(6,313)
Related party assets	(9,614)	(544)	(10,357)
Net cash provided by operating activities	1,452,756	1,729,610	1,946,235
Cash flow from investing activities:
Purchases of property, plant and equipment	(2,992,898)	(2,723,901)	(2,136,537)
Fixed maturity securities available-for-sale	(344,166)	(623,489)	(701,744)
Investments other	(174,967)	(213,264)	(158,408)
Proceeds from Sale of Held-to-maturity Securities	672,121	271,092	412,528
Net cash used by investing activities	2,046,373	2,421,385	1,867,176
Cash flow from financing activities:
Borrowings from credit facilities	1,186,363	1,017,898	1,969,474
Principal repayments on credit facilities	(919,771)	(801,994)	(437,506)
Debt issuance costs	(4,082)	(5,237)	(13,156)
Common stock dividends paid	0	(19,608)	(29,412)
Non-Voting Common Stock dividends paid	(31,765)	(14,117)	0
Net Cash Provided by (Used in) Financing Activities	66,533	59,795	1,433,155
Effects of exchange rate on cash	1,104	11,633	2,089
Increase (decrease) cash and cash equivalents	525,980	643,613	1,510,125
Cash and cash equivalents at the beginning of period	2,060,524	2,704,137	1,194,012
Cash and cash equivalents at the end of period	1,534,544	2,060,524	2,704,137
U-Haul Holding Company [Member]
Cash flow from operating activities:
Net Income (Loss)	628,707	924,472	1,124,362
Change in investments in subsidiaries	(160,302)	(582,517)	(1,012,917)
Adjustments to reconcile net earnings to cash provided by operations:
Depreciation	4	3	1
Amortization of debt issuance costs	859	859	292
Deferred income taxes, net	98,823	137,159	106,869
Net change in other operating assets and liabilities:
Prepaid expenses	(8,888)	6,120	234,490
Other assets	(10,753)	(2,884)	(4)
Related party assets		(120)	(240)
Accounts payable and accrued expenses	479	(2,499)	5,461
Net cash provided by operating activities	566,705	480,593	458,314
Cash flow from investing activities:
Purchases of property, plant and equipment	(3)	(1)	(11)
Fixed maturity securities available-for-sale	(170,317)	(224,999)	0
Investments other	(1,000)
Proceeds from Sale of Held-to-maturity Securities	322,330
Net cash used by investing activities	151,010	225,000	11
Cash flow from financing activities:
Borrowings from credit facilities			1,200,000
Debt issuance costs			(8,468)
Proceeds from (repayments) of intercompany loans	(1,373,275)	(637,585)	(284,438)
Common stock dividends paid		(19,608)	(29,412)
Non-Voting Common Stock dividends paid	(31,765)	(14,117)
Net Cash Provided by (Used in) Financing Activities	(1,405,040)	671,310	877,682
Effects of exchange rate on cash	356	6,940	1,591
Increase (decrease) cash and cash equivalents	687,681	422,657	1,334,394
Cash and cash equivalents at the beginning of period	1,662,790	2,085,447	751,053
Cash and cash equivalents at the end of period	$ 975,109	$ 1,662,790	$ 2,085,447