Schedule V - AMERCO and Consolidated Subsidiaries, Supplemental Information (for Property-Casualty Insurance Operations) (Details) - Amerco [Member] - Property Casualty Insurance Operations [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Supplemental information for property, casualty insurance underwriters:
Deferred policy acquisition costs
Reserves for unpaid claims and claims adjustment expense	244,400	251,964	271,609
Discount if any, deducted
Unearned premiums	49	59	49
Net earned premiums (1)	52,334	50,020	46,456
Net investment income (2)	14,015	13,491	11,980
Claim and claim adjustment expenses incurred related to current year	13,297	11,713	11,690
Claim and claim adjustment expenses incurred related to prior year	107	585	(694)
Amortization of deferred policy acquisition costs
Paid claims and claim adjustment expense	17,609	18,360	18,872
Net premiums written (1)	$ 52,324	$ 50,034	$ 46,452