Additional Paid In Capital and Insurance Subsidiaries Activity (Details) (USD $)	3 Months Ended	9 Months Ended
	Jun. 30, 2011	Dec. 31, 2012	Dec. 31, 2011
Additional paid in capital:
Payments for repurchase preferred stock		$ 0	$ 144,289,000
Series A preferred stock redemption date	Jun. 01, 2011
Insurance subsidiaries
Additional paid in capital:
Payments for repurchase preferred stock			8,000,000
Reduction of insurance company holdings			(6,000,000)
AMERCO /NV/
Additional paid in capital:
Prior to redemption additional paid-in capital cost			146,000,000
Payments for repurchase preferred stock			151,997,000
Series A preferred stock redemption date			Jun. 01, 2011
Payments for repurchase of preferred stock and preference stock			$ 153,000,000