Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Mar. 31, 2014
ASSETS:
Cash and cash equivalents	$ 729,023	$ 495,112
Reinsurance recoverables and trade receivables, net	197,640	199,322
Inventories, net	69,817	67,020
Prepaid expenses	94,076	55,269
Investments, fixed maturities and marketable equities	1,294,568	1,138,275
Investments, other	246,766	248,850
Deferred policy acquisition costs, net	116,191	118,707
Other assets	148,940	97,588
Related party assets	148,776	169,624
Subtotal assets	3,045,797	2,589,767
Property, plant and equipment, at cost:
Land	457,229	405,177
Buildings and improvements	1,641,420	1,430,330
Furniture and equipment	344,016	322,088
Property, plant and equipment (gross)	5,751,913	5,141,717
Less: Accumulated depreciation	(1,891,178)	(1,732,506)
Total property, plant and equipment	3,860,735	3,409,211
Total assets	6,906,532	5,998,978
Liabilities:
Accounts payable and accrued expenses	353,564	357,954
Notes, loans and leases payable	2,364,513	1,942,359
Policy benefits and losses, claims and loss expenses payable	1,063,986	1,082,598
Liabilities from investment contracts	673,051	616,725
Other policyholders' funds and liabilities	10,469	7,988
Deferred income	14,605	31,390
Deferred income taxes	519,936	432,596
Total liabilities	5,000,124	4,471,610
Commitments and contingencies (notes 4, 7 and 8)
Stockholders' equity:
Additional paid-in capital	449,156	444,210
Accumulated other comprehensive loss	(27,357)	(53,923)
Retained earnings	2,152,714	1,805,453
Unearned employee stock ownership plan shares	(952)	(1,219)
Total stockholders' equity	1,906,408	1,527,368
Total liabilities and stockholders' equity	6,906,532	5,998,978
Series A Preferred Stock [Member]
Stockholders' equity:
Preferred stock, value, issued
Series B Preferred Stock [Member]
Stockholders' equity:
Preferred stock, value, issued
Series A Common Stock [Member]
Stockholders' equity:
Common stock, value, issued
Amerco Common Stock [Member]
Stockholders' equity:
Common stock, value, issued	10,497	10,497
Common Stock in Treasury [Member]
Stockholders' equity:
Treasury stock, value	(525,653)	(525,653)
Preferred Stock in Treasury [Member]
Stockholders' equity:
Treasury stock, value	(151,997)	(151,997)
Rental Trailers and Other Rental Equipment [Member]
Property, plant and equipment, at cost:
Property subject to or available for operating lease, gross	428,197	373,325
Rental Trucks [Member]
Property, plant and equipment, at cost:
Property subject to or available for operating lease, gross	$ 2,881,051	$ 2,610,797