Consolidated Cash Flow Statement by Industry Segment (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Dec. 31, 2014		Dec. 31, 2013
Cash flow from operating activities:
Net earnings	$ 347,261		$ 303,180
Earnings from consolidated entities	0		0
Adjustments to reconcile net earnings to cash provided by operations:
Depreciation	259,871		214,268
Amortization of deferred policy acquisition costs	13,196		14,197
Change in allowance for losses on trade receivables	(212)		12
Change in allowance for inventory reserves	(744)		3,640
Net gain on sale of real and personal property	(49,944)		(22,837)
Net (gain) loss on sale of investments	(3,254)		(6,088)
Deferred income tax	71,485		48,033
Net change in other operating assets and liabilities:
Reinsurance recoverables and trade receivables	1,895		33,355
Inventories	(2,053)		(12,502)
Prepaid expenses	(38,905)		13,109
Capitalization of deferred policy acquisition costs	(20,158)		(25,128)
Other assets	(41,663)		7,929
Related party assets	20,770		5,630
Accounts payable and accrued expenses	(4,009)		(2,772)
Policy benefits and losses, claims and loss expenses payable	(17,587)		(18,337)
Other policyholders' funds and liabilities	2,482		(23)
Deferred income	(16,732)		(672)
Related party liabilities	22		6,257
Net cash provided by operating activities	521,721		561,251
Purchase of:
Property, plant and equipment	(725,447)		(690,293)
Short term investments	(203,018)		(203,763)
Fixed maturities investments	(181,824)		(237,502)
Equity securities	(3,759)		(388)
Preferred stock	(5)		(635)
Real estate	(11,328)		(431)
Mortgage loans	(37,365)		(48,632)
Proceeds from sale of:
Property, plant and equipment	321,680		214,078
Short term investments	220,610		211,841
Fixed maturities investments	75,372		124,145
Equity securities	3,082		26,957
Preferred stock	2,027		6,004
Real estate	396
Mortgage loans	33,192		45,234
Net cash used by investing activities	(506,387)		(553,385)
Cash flow from financing activities:
Borrowings from credit facilities	510,074		323,039
Principal repayments on credit facilities	(266,672)		(238,553)
Debt issuance costs	(9,697)		(3,353)
Capital lease payments	(65,478)		(37,480)
Leveraged Employee Stock Ownership Plan - repayments from loan	267		390
Proceeds from (repayment of) intercompany loans	0		0
Investment contract deposits	94,979		109,928
Investment contract withdrawals	(38,653)		(24,448)
Net cash provided by financing activities	224,820		129,523
Effects of exchange rate on cash	(6,243)		482
Increase (decrease) in cash and cash equivalents	233,911		137,871
Cash and cash equivalents at the beginning of period	495,112		463,744
Cash and cash equivalents at the end of the period	729,023		601,615
Operating Segments [Member] | Moving and Storage Consolidations [Member]
Cash flow from operating activities:
Net earnings	347,261		303,180
Earnings from consolidated entities	(25,763)		(23,864)
Adjustments to reconcile net earnings to cash provided by operations:
Depreciation	259,871		214,268
Amortization of deferred policy acquisition costs	0		0
Change in allowance for losses on trade receivables	(201)		3
Change in allowance for inventory reserves	(744)		3,640
Net gain on sale of real and personal property	(49,944)		(22,837)
Net (gain) loss on sale of investments	0		(1,325)
Deferred income tax	64,058		37,934
Net change in other operating assets and liabilities:
Reinsurance recoverables and trade receivables	(9,126)		13,233
Inventories	(2,053)		(12,502)
Prepaid expenses	(38,905)		13,109
Capitalization of deferred policy acquisition costs	0		0
Other assets	(41,905)		7,848
Related party assets	21,474		10,173
Accounts payable and accrued expenses	(13,546)		(15,990)
Policy benefits and losses, claims and loss expenses payable	(4,623)		1,218
Other policyholders' funds and liabilities	0		0
Deferred income	(16,732)		(672)
Related party liabilities	(235)		3,263
Net cash provided by operating activities	488,887		530,679
Purchase of:
Property, plant and equipment	(725,447)		(690,293)
Short term investments	0		0
Fixed maturities investments	0		0
Equity securities	0		0
Preferred stock	0		0
Real estate	0		0
Mortgage loans	(21,593)		(19,262)
Proceeds from sale of:
Property, plant and equipment	321,680		214,078
Short term investments	0		0
Fixed maturities investments	0		0
Equity securities	0		26,569
Preferred stock	0		0
Real estate	0		0
Mortgage loans	23,214		37,564
Net cash used by investing activities	(402,146)		(431,344)
Cash flow from financing activities:
Borrowings from credit facilities	510,074		323,039
Principal repayments on credit facilities	(266,672)		(238,553)
Debt issuance costs	(9,697)		(3,353)
Capital lease payments	(65,478)		(37,480)
Leveraged Employee Stock Ownership Plan - repayments from loan	267		390
Proceeds from (repayment of) intercompany loans	0		0
Investment contract deposits	0		0
Investment contract withdrawals	0		0
Net cash provided by financing activities	168,494		44,043
Effects of exchange rate on cash	(6,243)		482
Increase (decrease) in cash and cash equivalents	248,992		143,860
Cash and cash equivalents at the beginning of period	464,710		427,560
Cash and cash equivalents at the end of the period	713,702		571,420
Operating Segments [Member] | Moving and Storage Consolidations [Member] | AMERCO [Member]
Cash flow from operating activities:
Net earnings	347,261		303,180
Earnings from consolidated entities	(313,319)		(263,524)
Adjustments to reconcile net earnings to cash provided by operations:
Depreciation	4		4
Amortization of deferred policy acquisition costs	0		0
Change in allowance for losses on trade receivables	0		0
Change in allowance for inventory reserves	0		0
Net gain on sale of real and personal property	0		0
Net (gain) loss on sale of investments	0		(1,325)
Deferred income tax	64,058		37,934
Net change in other operating assets and liabilities:
Reinsurance recoverables and trade receivables	0		0
Inventories	0		0
Prepaid expenses	(24,278)		22,475
Capitalization of deferred policy acquisition costs	0		0
Other assets	(36,897)		5
Related party assets	(534)		540
Accounts payable and accrued expenses	4,614		6,563
Policy benefits and losses, claims and loss expenses payable	0		0
Other policyholders' funds and liabilities	0		0
Deferred income	0		0
Related party liabilities	0		0
Net cash provided by operating activities	40,909		105,852
Purchase of:
Property, plant and equipment	0		0
Short term investments	0		0
Fixed maturities investments	0		0
Equity securities	0		0
Preferred stock	0		0
Real estate	0		0
Mortgage loans	0		0
Proceeds from sale of:
Property, plant and equipment	0		0
Short term investments	0		0
Fixed maturities investments	0		0
Equity securities	0		26,569
Preferred stock	0		0
Real estate	0		0
Mortgage loans	0		0
Net cash used by investing activities	0		26,569
Cash flow from financing activities:
Borrowings from credit facilities	0		0
Principal repayments on credit facilities	0		0
Debt issuance costs	0		0
Capital lease payments	0		0
Leveraged Employee Stock Ownership Plan - repayments from loan	0		0
Proceeds from (repayment of) intercompany loans	(26,894)		17,011
Investment contract deposits	0		0
Investment contract withdrawals	0		0
Net cash provided by financing activities	26,894		17,011
Effects of exchange rate on cash	0
Increase (decrease) in cash and cash equivalents	14,015		149,432
Cash and cash equivalents at the beginning of period	321,544		327,119
Cash and cash equivalents at the end of the period	335,559		476,551
Operating Segments [Member] | Moving and Storage Consolidations [Member] | Uhaul [Member]
Cash flow from operating activities:
Net earnings	290,137		235,997
Earnings from consolidated entities	0		0
Adjustments to reconcile net earnings to cash provided by operations:
Depreciation	242,708		201,286
Amortization of deferred policy acquisition costs	0		0
Change in allowance for losses on trade receivables	(201)		3
Change in allowance for inventory reserves	(744)		3,640
Net gain on sale of real and personal property	(49,948)		(22,045)
Net (gain) loss on sale of investments	0		0
Deferred income tax	0		0
Net change in other operating assets and liabilities:
Reinsurance recoverables and trade receivables	(9,126)		13,410
Inventories	(2,053)		(12,502)
Prepaid expenses	(13,918)		(8,660)
Capitalization of deferred policy acquisition costs	0		0
Other assets	(4,316)		10,558
Related party assets	22,008		9,636
Accounts payable and accrued expenses	(19,545)		(22,843)
Policy benefits and losses, claims and loss expenses payable	(4,623)		1,218
Other policyholders' funds and liabilities	0		0
Deferred income	(16,743)		(672)
Related party liabilities	(168)		(1,007)
Net cash provided by operating activities	433,468		408,019
Purchase of:
Property, plant and equipment	(534,117)		(436,671)
Short term investments	0		0
Fixed maturities investments	0		0
Equity securities	0		0
Preferred stock	0		0
Real estate	0		0
Mortgage loans	0		(1,580)
Proceeds from sale of:
Property, plant and equipment	321,495		212,601
Short term investments	0		0
Fixed maturities investments	0		0
Equity securities	0		0
Preferred stock	0		0
Real estate	0		0
Mortgage loans	1,653		1,680
Net cash used by investing activities	(210,969)		(223,970)
Cash flow from financing activities:
Borrowings from credit facilities	156,251		116,952
Principal repayments on credit facilities	(90,154)		(149,948)
Debt issuance costs	(53)		(641)
Capital lease payments	(65,478)		(37,480)
Leveraged Employee Stock Ownership Plan - repayments from loan	267		390
Proceeds from (repayment of) intercompany loans	16,110		(120,035)
Investment contract deposits	0		0
Investment contract withdrawals	0		0
Net cash provided by financing activities	16,943		(190,762)
Effects of exchange rate on cash	(6,243)		482
Increase (decrease) in cash and cash equivalents	233,199		(6,231)
Cash and cash equivalents at the beginning of period	140,844		98,926
Cash and cash equivalents at the end of the period	374,043		92,695
Operating Segments [Member] | Moving and Storage Consolidations [Member] | Real Estate [Member]
Cash flow from operating activities:
Net earnings	(2,581)		3,663
Earnings from consolidated entities	0		0
Adjustments to reconcile net earnings to cash provided by operations:
Depreciation	17,159		12,978
Amortization of deferred policy acquisition costs	0		0
Change in allowance for losses on trade receivables	0		0
Change in allowance for inventory reserves	0		0
Net gain on sale of real and personal property	4		(792)
Net (gain) loss on sale of investments	0		0
Deferred income tax	0		0
Net change in other operating assets and liabilities:
Reinsurance recoverables and trade receivables	0		(177)
Inventories	0		0
Prepaid expenses	(709)		(706)
Capitalization of deferred policy acquisition costs	0		0
Other assets	(692)		(2,715)
Related party assets	0		(3)
Accounts payable and accrued expenses	1,385		290
Policy benefits and losses, claims and loss expenses payable	0		0
Other policyholders' funds and liabilities	0		0
Deferred income	11		0
Related party liabilities	(67)		4,270
Net cash provided by operating activities	14,510		16,808
Purchase of:
Property, plant and equipment	(191,330)		(253,622)
Short term investments	0		0
Fixed maturities investments	0		0
Equity securities	0		0
Preferred stock	0		0
Real estate	0		0
Mortgage loans	(21,593)		(20,196)
Proceeds from sale of:
Property, plant and equipment	185		1,477
Short term investments	0		0
Fixed maturities investments	0		0
Equity securities	0		0
Preferred stock	0		0
Real estate	0		0
Mortgage loans	21,561		38,398
Net cash used by investing activities	(191,177)		(233,943)
Cash flow from financing activities:
Borrowings from credit facilities	353,823		206,087
Principal repayments on credit facilities	(176,518)		(88,605)
Debt issuance costs	(9,644)		(2,712)
Capital lease payments	0		0
Leveraged Employee Stock Ownership Plan - repayments from loan	0		0
Proceeds from (repayment of) intercompany loans	10,784		103,024
Investment contract deposits	0		0
Investment contract withdrawals	0		0
Net cash provided by financing activities	178,445		217,794
Effects of exchange rate on cash	0		0
Increase (decrease) in cash and cash equivalents	1,778		659
Cash and cash equivalents at the beginning of period	2,322		1,515
Cash and cash equivalents at the end of the period	4,100		2,174
Operating Segments [Member] | Moving and Storage Consolidations [Member] | Moving and Storage Operating Eliminations [Member]
Cash flow from operating activities:
Net earnings	(287,556)		(239,660)
Earnings from consolidated entities	287,556		239,660
Adjustments to reconcile net earnings to cash provided by operations:
Depreciation	0		0
Amortization of deferred policy acquisition costs	0		0
Change in allowance for losses on trade receivables	0		0
Change in allowance for inventory reserves	0		0
Net gain on sale of real and personal property	0		0
Net (gain) loss on sale of investments	0		0
Deferred income tax	0		0
Net change in other operating assets and liabilities:
Reinsurance recoverables and trade receivables	0		0
Inventories	0		0
Prepaid expenses	0		0
Capitalization of deferred policy acquisition costs	0		0
Other assets	0		0
Related party assets	0		0
Accounts payable and accrued expenses	0		0
Policy benefits and losses, claims and loss expenses payable	0		0
Other policyholders' funds and liabilities	0		0
Deferred income	0		0
Related party liabilities	0		0
Net cash provided by operating activities	0		0
Purchase of:
Property, plant and equipment	0		0
Short term investments	0		0
Fixed maturities investments	0		0
Equity securities	0		0
Preferred stock	0		0
Real estate	0		0
Mortgage loans	0		2,514	[1]
Proceeds from sale of:
Property, plant and equipment	0		0
Short term investments	0		0
Fixed maturities investments	0		0
Equity securities	0		0
Preferred stock	0		0
Real estate	0		0
Mortgage loans	0		(2,514)	[1]
Net cash used by investing activities	0		0
Cash flow from financing activities:
Borrowings from credit facilities	0		0
Principal repayments on credit facilities	0		0
Debt issuance costs	0		0
Capital lease payments	0		0
Leveraged Employee Stock Ownership Plan - repayments from loan	0		0
Proceeds from (repayment of) intercompany loans	0		0
Investment contract deposits	0		0
Investment contract withdrawals	0		0
Net cash provided by financing activities	0		0
Effects of exchange rate on cash	0		0
Increase (decrease) in cash and cash equivalents	0		0
Cash and cash equivalents at the beginning of period	0		0
Cash and cash equivalents at the end of the period	0		0
Operating Segments [Member] | Property and Casualty Insurance [Member]
Cash flow from operating activities:
Net earnings	11,658	[2]	10,737	[3]
Earnings from consolidated entities	0	[2]	0	[3]
Adjustments to reconcile net earnings to cash provided by operations:
Depreciation	0	[2]	0	[3]
Amortization of deferred policy acquisition costs	0	[4]	0	[5]
Change in allowance for losses on trade receivables	0	[2]	0	[3]
Change in allowance for inventory reserves	0	[2]	0	[3]
Net gain on sale of real and personal property	0	[2]	0	[3]
Net (gain) loss on sale of investments	(839)	[2]	(674)	[3]
Deferred income tax	4,983	[2]	5,118	[3]
Net change in other operating assets and liabilities:
Reinsurance recoverables and trade receivables	17,101	[2]	23,296	[3]
Inventories	0	[2]	0	[3]
Prepaid expenses	0	[2]	0	[3]
Capitalization of deferred policy acquisition costs	0	[2]	0	[3]
Other assets	1,088	[2]	201	[3]
Related party assets	(947)	[2]	(4,702)	[3]
Accounts payable and accrued expenses	0	[2]	0	[3]
Policy benefits and losses, claims and loss expenses payable	(21,913)	[2]	(29,833)	[3]
Other policyholders' funds and liabilities	1,147	[2]	(39)	[3]
Deferred income	0	[2]	0	[3]
Related party liabilities	285	[2]	2,850	[3]
Net cash provided by operating activities	12,563	[2]	6,954	[3]
Purchase of:
Property, plant and equipment	0	[2]	0	[3]
Short term investments	(35,624)	[2]	(35,250)	[3]
Fixed maturities investments	(33,735)	[2]	(50,840)	[3]
Equity securities	(3,333)	[2]	(388)	[3]
Preferred stock	(5)	[2]	(635)	[3]
Real estate	(3,812)	[2]	0	[3]
Mortgage loans	(3,150)	[2]	(3,500)	[3]
Proceeds from sale of:
Property, plant and equipment	0	[2]	0	[3]
Short term investments	39,745	[2]	50,044	[3]
Fixed maturities investments	17,794	[2]	14,892	[3]
Equity securities	3,082	[2]	388	[3]
Preferred stock	0	[2]	4,504	[3]
Real estate	0	[2]	0	[3]
Mortgage loans	3,976	[2]	5,312	[3]
Net cash used by investing activities	(15,062)	[2]	(15,473)	[3]
Cash flow from financing activities:
Borrowings from credit facilities	0	[2]	0	[3]
Principal repayments on credit facilities	0	[2]	0	[3]
Debt issuance costs	0	[2]	0	[3]
Capital lease payments	0	[2]	0	[3]
Leveraged Employee Stock Ownership Plan - repayments from loan	0	[2]	0	[3]
Proceeds from (repayment of) intercompany loans	0	[2]	0	[3]
Investment contract deposits	0	[2]	0	[3]
Investment contract withdrawals	0	[2]	0	[3]
Net cash provided by financing activities	0	[2]	0	[3]
Effects of exchange rate on cash	0	[2]	0	[3]
Increase (decrease) in cash and cash equivalents	(2,499)	[2]	(8,519)	[3]
Cash and cash equivalents at the beginning of period	12,758	[2]	14,120	[3]
Cash and cash equivalents at the end of the period	10,259	[2]	5,601	[3]
Operating Segments [Member] | Life Insurance [Member]
Cash flow from operating activities:
Net earnings	14,105	[2]	13,127	[3]
Earnings from consolidated entities	0	[2]	0	[3]
Adjustments to reconcile net earnings to cash provided by operations:
Depreciation	0	[2]	0	[3]
Amortization of deferred policy acquisition costs	13,196	[4]	14,197	[5]
Change in allowance for losses on trade receivables	(11)	[2]	9	[3]
Change in allowance for inventory reserves	0	[2]	0	[3]
Net gain on sale of real and personal property	0	[2]	0	[3]
Net (gain) loss on sale of investments	(2,415)	[2]	(4,089)	[3]
Deferred income tax	2,444	[2]	4,981	[3]
Net change in other operating assets and liabilities:
Reinsurance recoverables and trade receivables	(6,080)	[2]	(3,174)	[3]
Inventories	0	[2]	0	[3]
Prepaid expenses	0	[2]	0	[3]
Capitalization of deferred policy acquisition costs	(20,158)	[2]	(25,128)	[3]
Other assets	(846)	[2]	(120)	[3]
Related party assets	0	[2]	0	[3]
Accounts payable and accrued expenses	9,537	[2]	13,218	[3]
Policy benefits and losses, claims and loss expenses payable	8,949	[2]	10,278	[3]
Other policyholders' funds and liabilities	1,335	[2]	16	[3]
Deferred income	0	[2]	0	[3]
Related party liabilities	215	[2]	303	[3]
Net cash provided by operating activities	20,271	[2]	23,618	[3]
Purchase of:
Property, plant and equipment	0	[2]	0	[3]
Short term investments	(167,394)	[2]	(168,513)	[3]
Fixed maturities investments	(148,089)	[2]	(186,662)	[3]
Equity securities	(426)	[2]	0	[3]
Preferred stock	0	[2]	0	[3]
Real estate	(7,516)	[2]	(431)	[3]
Mortgage loans	(12,622)	[2]	(37,459)	[3]
Proceeds from sale of:
Property, plant and equipment	0	[2]	0	[3]
Short term investments	180,865	[2]	161,797	[3]
Fixed maturities investments	57,578	[2]	109,253	[3]
Equity securities	0	[2]	0	[3]
Preferred stock	2,027	[2]	1,500	[3]
Real estate	396	[2]	0	[3]
Mortgage loans	6,002	[2]	13,947	[3]
Net cash used by investing activities	(89,179)	[2]	(106,568)	[3]
Cash flow from financing activities:
Borrowings from credit facilities	0	[2]	0	[3]
Principal repayments on credit facilities	0	[2]	0	[3]
Debt issuance costs	0	[2]	0	[3]
Capital lease payments	0	[2]	0	[3]
Leveraged Employee Stock Ownership Plan - repayments from loan	0	[2]	0	[3]
Proceeds from (repayment of) intercompany loans	0	[2]	0	[3]
Investment contract deposits	94,979	[2]	109,928	[3]
Investment contract withdrawals	(38,653)	[2]	(24,448)	[3]
Net cash provided by financing activities	56,326	[2]	85,480	[3]
Effects of exchange rate on cash	0	[2]	0	[3]
Increase (decrease) in cash and cash equivalents	(12,582)	[2]	2,530	[3]
Cash and cash equivalents at the beginning of period	17,644	[2]	22,064	[3]
Cash and cash equivalents at the end of the period	5,062	[2]	24,594	[3]
Consolidation, Eliminations [Member]
Cash flow from operating activities:
Net earnings	(25,763)		(23,864)
Earnings from consolidated entities	25,763		23,864
Adjustments to reconcile net earnings to cash provided by operations:
Depreciation	0		0
Amortization of deferred policy acquisition costs	0		0
Change in allowance for losses on trade receivables	0		0
Change in allowance for inventory reserves	0		0
Net gain on sale of real and personal property	0		0
Net (gain) loss on sale of investments	0		0
Deferred income tax	0		0
Net change in other operating assets and liabilities:
Reinsurance recoverables and trade receivables	0		0
Inventories	0		0
Prepaid expenses	0		0
Capitalization of deferred policy acquisition costs	0		0
Other assets	0		0
Related party assets	243	[1]	159	[1]
Accounts payable and accrued expenses	0		0
Policy benefits and losses, claims and loss expenses payable	0		0
Other policyholders' funds and liabilities	0		0
Deferred income	0		0
Related party liabilities	(243)	[1]	(159)	[1]
Net cash provided by operating activities	0		0
Purchase of:
Property, plant and equipment	0		0
Short term investments	0		0
Fixed maturities investments	0		0
Equity securities	0		0
Preferred stock	0		0
Real estate	0		0
Mortgage loans	0		11,589	[1]
Proceeds from sale of:
Property, plant and equipment	0		0
Short term investments	0		0
Fixed maturities investments	0		0
Equity securities	0		0
Preferred stock	0		0
Real estate	0		0
Mortgage loans	0		(11,589)	[1]
Net cash used by investing activities	0		0
Cash flow from financing activities:
Borrowings from credit facilities	0		0
Principal repayments on credit facilities	0		0
Debt issuance costs	0		0
Capital lease payments	0		0
Leveraged Employee Stock Ownership Plan - repayments from loan	0		0
Proceeds from (repayment of) intercompany loans	0		0
Investment contract deposits	0		0
Investment contract withdrawals	0		0
Net cash provided by financing activities	0		0
Effects of exchange rate on cash	0		0
Increase (decrease) in cash and cash equivalents	0		0
Cash and cash equivalents at the beginning of period	0		0
Cash and cash equivalents at the end of the period	$ 0		$ 0

[1] Elimination of interecompany investments

[2] Balance for the period ended September 30, 2014

[3] Balance for the period ended September 30, 2013

[4] Balances for the nine months ended September 30, 2014

[5] Balances for the nine months ended September 30, 2013