Schedule I - Condensed Financial Information of AMERCO (Statements of Cash Flow) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Cash flow from operating activities:
Net earnings	$ 489,001	$ 356,741	$ 342,391
Earnings from consolidated subsidiaries
Adjustments to reconcile net earnings to cash provided by operations:
Depreciation	$ 389,393	$ 352,796	$ 293,169
Net gain (loss) on sale of investments	(4,491)	(3,925)	(6,411)
Deferred income taxes	138,075	76,500	46,371
Net change in other operating assets and liabilities:
Prepaid expenses	(10,338)	(65,720)	2,186
Other assets	15,322	3,735	7,667
Related party assets	56,644	27,706	7,554
Accounts payable and accrued expenses	37,387	98,877	36,365
Net cash provided by operating activities	1,041,063	759,099	733,966
Cash flow from investing activities:
Purchases of property, plant and equipment	(1,509,154)	(1,041,931)	(1,000,243)
Proceeds of equity securities	2,044	3,082	29,139
Net cash used by investing activities	(1,273,399)	(755,261)	(846,631)
Cash flow from financing activities:
Common stock dividends paid	(78,374)	(19,594)	(19,568)
Net cash provided by financing activities	406,872	(46,338)	144,210
Increase (decrease) in cash and cash equivalents	158,796	(53,262)	31,368
Cash and cash equivalents at the beginning of period	441,850	495,112	463,744
Cash and cash equivalents at the end of the period	600,646	441,850	495,112
Amerco [Member]
Cash flow from operating activities:
Net earnings	489,001	356,741	342,391
Earnings from consolidated subsidiaries	(417,087)	(300,566)	(287,803)
Adjustments to reconcile net earnings to cash provided by operations:
Depreciation	$ 6	$ 6	5
Net gain (loss) on sale of investments			(1,325)
Deferred income taxes	$ 124,838	$ 66,628	34,605
Net change in other operating assets and liabilities:
Prepaid expenses	(8,723)	(66,786)	3,938
Other assets	6	84	$ (41)
Related party assets	56,849	(539)
Accounts payable and accrued expenses	(14)	5,239	$ 6,589
Net cash provided by operating activities	244,876	$ 60,807	98,359
Cash flow from investing activities:
Purchases of property, plant and equipment	$ (8)		(2)
Proceeds of equity securities			26,569
Net cash used by investing activities	$ (8)		26,567
Cash flow from financing activities:
Proceeds from (repayments) of intercompany loans	(76,354)	$ (71,207)	(110,933)
Common stock dividends paid	(78,374)	(19,594)	(19,568)
Net cash provided by financing activities	(154,728)	(90,801)	(130,501)
Increase (decrease) in cash and cash equivalents	90,140	(29,994)	(5,575)
Cash and cash equivalents at the beginning of period	291,550	321,544	327,119
Cash and cash equivalents at the end of the period	$ 381,690	$ 291,550	$ 321,544