Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2021
Revenues:
Self-moving equipment rentals	$ 3,877,917	$ 3,958,807	$ 3,083,317
Self-storage revenues	744,492	617,120	477,262
Self-moving and self-storage products and service sales	357,286	351,447	344,929
Property management fees	37,073	35,194	31,603
Life insurance premiums	99,149	111,027	121,609
Property and casualty insurance premiums	93,209	86,518	68,779
Net investment and interest income	176,679	148,261	122,938
Other revenue	478,886	431,373	291,548
Total revenues	5,864,691	5,739,747	4,541,985
Costs and expenses:
Operating expenses	3,024,547	2,676,541	2,187,684
Commission expenses	416,315	429,581	329,609
Cost of sales	263,026	259,585	214,059
Benefits and losses	165,553	186,647	179,512
Amortization of deferred policy acquisition costs	27,924	33,854	28,293
Lease expense	30,829	29,910	28,470
Depreciation, net of (gains) losses on disposals	486,795	482,752	609,930
Net gains on disposal of real estate	5,596	(4,120)	3,281
Total costs and expenses	4,420,585	4,094,750	3,580,838
Earnings from operations	1,444,106	1,644,997	961,147
Other components of net periodic benefit costs	(1,216)	(1,120)	(987)
Interest expense	(223,958)	(167,424)	(163,502)
Fees and amortization on early extinguishment of debt	(1,009)	(956)	0
Pretax earnings	1,217,923	1,475,497	796,658
Income tax expense	(294,925)	(352,211)	(185,802)
Earnings available to common shareholders	922,998	1,123,286	610,856
Common Stock [Member]
Costs and expenses:
Earnings available to common shareholders	$ 0	$ 0	$ 0
Basic and diluted earnings per common share	$ 5.54	$ 7.08	$ 5.37
Weighted average common shares outstanding: basic and diluted	19,607,788	19,607,788	19,607,788
Nonvoting Common Stock [Member]
Costs and expenses:
Earnings available to common shareholders	$ 0	$ 0	$ 0
Basic and diluted earnings per common share	$ 4.62	$ 5.58	$ 2.87
Weighted average common shares outstanding: basic and diluted	176,470,092	176,470,092	176,470,092
Nonvoting Common Stock [Member] | Common Stock [Member]
Costs and expenses:
Weighted average common shares outstanding: basic and diluted	196,077,880	196,077,880	196,077,880