Schedule V, AMERCO and Consolidated Subsidiaries, Supplemental Information (for Property-Casualty Insurance Operations) (Details) (Consolidated property casualty entity [Member], AMERCO [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Consolidated property casualty entity [Member] | AMERCO [Member]
Supplemental information for property, casualty insurance underwriters:
Deferred policy acquisition costs
Reserves for unpaid claims and claims adjustment expense	271,609	295,126	330,093
Discount if any, deducted
Unearned premiums
Net earned premiums (1)	46,456	41,052	34,342
Net investment income (2)	11,980	10,057	8,976
Claim and claim adjustment expenses incurred related to current year	11,690	9,861	8,962
Claim and claim adjustment expenses incurred related to prior year	(694)	1,652	7,036
Amortization of deferred policy acquisition costs
Paid claims and claim adjustment expense	18,872	6,576	20,807
Net premiums written (1)	$ 46,452	$ 41,065	$ 34,378