Consolidated Cash Flow Statement by Industry Segment (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Mar. 31, 2015		Mar. 31, 2014		Mar. 31, 2013
Cash flow from operating activities:
Net earnings	$ 356,741		$ 342,391		$ 264,708
Earnings from consolidated subsidiaries	0		0		0
Adjustments to reconcile net earnings to cash provided by operations:
Depreciation	352,796		293,169		260,492
Amortization of deferred policy acquisition costs	19,661		19,982		17,376
Change in allowance for losses on trade receivables	(168)		(36)		(134)
Change in allowance for inventory reserves	(872)		871		1,133
Net gain on sale of real and personal property	(74,631)		(33,557)		(22,496)
Net (gain) loss on sale of investments	(3,925)		(6,411)		(8,323)
Deferred income taxes	76,500		46,371		13,518
Net change in other operating assets and liabilities:
Reinsurance recoverables and trade receivables	9,632		62,506		36,322
Inventories	(1,579)		(11,495)		1,206
Prepaid expenses	(65,720)		2,186		(15,587)
Capitalization of deferred policy acquisition costs	(27,084)		(32,611)		(50,640)
Other assets	3,735		7,667		21,556
Related party assets	27,706		7,554		133,672
Accounts payable and accrued expenses	166,056		34,731		40,032
Policy benefits and losses, claims and loss expenses payable	(17,621)		(30,496)		(30,478)
Other policyholders' funds and liabilities	1,010		693		21
Deferred income	(13,181)		1,259		(1,312)
Related party liabilities	(866)		4,730		464
Net cash provided by operating activities	808,190		709,504		661,530
Cash flow from investing activities:
Property, plant and equipment	(1,111,899)		(999,365)		(655,984)
Short term investments	(290,379)		(270,690)		(411,638)
Fixed maturities investments	(214,371)		(282,424)		(443,262)
Equity securities	(3,759)		(1,562)		(16,289)
Preferred stock	(2,006)		(640)		(6,296)
Real estate	(15,399)		(532)		(1,073)
Mortgage loans	(42,683)		(52,419)		(80,711)
Proceeds from sale and paydowns of:
Property, plant and equipment	411,629		270,053		220,699
Short term investments	287,883		269,052		417,520
Fixed maturities investments	107,867		138,401		160,806
Equity securities	3,082		29,139		372
Preferred stock	2,427		6,004		7,258
Real estate	396		544		671
Mortgage loans	41,983		48,686		95,714
Net cash used by investing activities	(825,229)		(845,753)		(712,213)
Cash flow from financing activities:
Borrowings from credit facilities	657,535		431,029		270,546
Principal repayments on credit facilities	(593,722)		(293,068)		(257,957)
Debt issuance costs	(12,327)		(3,943)		(2,223)
Capital lease payments	(121,202)		(53,079)		(26,877)
Leveraged Employee Stock Ownership Plan	(5,172)		487		692
Securitization deposits	0		0		1,195
Proceeds from (repayment of) intercompany loans	0		0		0
Common stock dividends paid	(19,594)		(19,568)		(97,421)
Contribution to related party					0
Investment contract deposits	123,129		140,613		301,729
Investment contract withdrawals	(54,108)		(34,677)		(31,901)
Net cash provided by financing activities	(25,461)		167,794		157,783
Effects of exchange rate on cash	(10,762)		(177)		(536)
Increase (decrease) in cash and cash equivalents	(53,262)		31,368		106,564
Cash and cash equivalents at the beginning of period	495,112		463,744		357,180
Cash and cash equivalents at the end of the period	441,850		495,112		463,744
Operating Segments [Member] | Moving and Storage Consolidations [Member]
Cash flow from operating activities:
Net earnings	356,741		342,391		264,708
Earnings from consolidated subsidiaries	(34,783)		(29,992)		(24,241)
Adjustments to reconcile net earnings to cash provided by operations:
Depreciation	352,796		293,169		260,492
Amortization of deferred policy acquisition costs	0		0		0
Change in allowance for losses on trade receivables	(179)		(28)		(134)
Change in allowance for inventory reserves	(872)		871		1,133
Net gain on sale of real and personal property	(74,631)		(33,557)		(22,496)
Net (gain) loss on sale of investments	0		(1,325)		(76)
Deferred income taxes	66,628		34,605		9,206
Net change in other operating assets and liabilities:
Reinsurance recoverables and trade receivables	(3,213)		14,328		(6,022)
Inventories	(1,579)		(11,495)		1,206
Prepaid expenses	(65,720)		2,186		(15,587)
Capitalization of deferred policy acquisition costs	0		0		0
Other assets	4,437		8,670		21,216
Related party assets	27,753		11,060		133,970
Accounts payable and accrued expenses	158,610		30,822		41,330
Policy benefits and losses, claims and loss expenses payable	(4,327)		(8,202)		1,102
Other policyholders' funds and liabilities	0		0		0
Deferred income	(13,181)		1,259		(1,312)
Related party liabilities	(1,016)		5,647		1,145
Net cash provided by operating activities	767,464		660,409		665,640
Cash flow from investing activities:
Property, plant and equipment	(1,111,899)		(999,365)		(655,984)
Short term investments	0		0		0
Fixed maturities investments	0		0		0
Equity securities	0		0		0
Preferred stock	0		0		0
Real estate	0		0		(243)
Mortgage loans	(22,876)		(21,349)		(45,206)
Proceeds from sale and paydowns of:
Property, plant and equipment	411,629		270,053		220,699
Short term investments	0		0		0
Fixed maturities investments	0		0		0
Equity securities	0		26,569		372
Preferred stock	0		0		0
Real estate	0		193		667
Mortgage loans	28,089		38,959		46,468
Net cash used by investing activities	(695,057)		(684,940)		(433,227)
Cash flow from financing activities:
Borrowings from credit facilities	657,535		431,029		270,546
Principal repayments on credit facilities	(593,722)		(293,068)		(257,957)
Debt issuance costs	(12,327)		(3,943)		(2,223)
Capital lease payments	(121,202)		(53,079)		(26,877)
Leveraged Employee Stock Ownership Plan	(5,172)		487		692
Securitization deposits			0		1,195
Proceeds from (repayment of) intercompany loans	0		0		0
Common stock dividends paid	(19,594)		(19,568)		(97,421)
Contribution to related party			0		(1,500)
Investment contract deposits	0		0		0
Investment contract withdrawals	0		0		0
Net cash provided by financing activities	(94,482)		61,858		(113,545)
Effects of exchange rate on cash	(10,762)		(177)		(536)
Increase (decrease) in cash and cash equivalents	(32,837)		37,150		118,332
Cash and cash equivalents at the beginning of period	464,710		427,560		309,228
Cash and cash equivalents at the end of the period	431,873		464,710		427,560
Operating Segments [Member] | Property and Casualty Insurance [Member]
Cash flow from operating activities:
Net earnings	15,417	[1]	12,662	[2]	9,256	[3]
Earnings from consolidated subsidiaries	0	[1]	0	[2]	0	[3]
Adjustments to reconcile net earnings to cash provided by operations:
Depreciation	0	[1]	0	[2]	0	[3]
Amortization of deferred policy acquisition costs	0	[4]	0	[5]	0	[6]
Change in allowance for losses on trade receivables	0	[1]	0	[2]	0	[3]
Change in allowance for inventory reserves	0	[1]	0	[2]	0	[3]
Net gain on sale of real and personal property	0	[1]	0	[2]	0	[3]
Net (gain) loss on sale of investments	(841)	[1]	(536)	[2]	(4,883)	[3]
Deferred income taxes	8,030	[1]	7,301	[2]	4,459	[3]
Net change in other operating assets and liabilities:
Reinsurance recoverables and trade receivables	16,830	[1]	43,675	[2]	45,201	[3]
Inventories	0	[1]	0	[2]	0	[3]
Prepaid expenses	0	[1]	0	[2]	0	[3]
Capitalization of deferred policy acquisition costs	0	[1]	0	[2]	0	[3]
Other assets	102	[1]	(781)	[2]	294	[3]
Related party assets	(258)	[1]	(4,231)	[2]	(1,361)	[3]
Accounts payable and accrued expenses	0	[1]	0	[2]	0	[3]
Policy benefits and losses, claims and loss expenses payable	(23,472)	[1]	(34,968)	[2]	(52,755)	[3]
Other policyholders' funds and liabilities	339	[1]	575	[2]	(281)	[3]
Deferred income	0	[1]	0	[2]	0	[3]
Related party liabilities	428	[1]	(131)	[2]	346	[3]
Net cash provided by operating activities	16,575	[1]	23,566	[2]	276	[3]
Cash flow from investing activities:
Property, plant and equipment	0	[1]	0	[2]	0	[3]
Short term investments	(40,583)	[1]	(60,551)	[2]	(97,269)	[3]
Fixed maturities investments	(43,062)	[1]	(58,790)	[2]	(44,460)	[3]
Equity securities	(3,333)	[1]	(746)	[2]	(16,289)	[3]
Preferred stock	(1,006)	[1]	(640)	[2]	(6,296)	[3]
Real estate	(7,857)	[1]	0	[2]	0	[3]
Mortgage loans	(4,350)	[1]	(3,500)	[2]	(1,821)	[3]
Proceeds from sale and paydowns of:
Property, plant and equipment	0	[1]	0	[2]	0	[3]
Short term investments	53,112	[1]	68,852	[2]	87,738	[3]
Fixed maturities investments	18,556	[1]	17,106	[2]	35,493	[3]
Equity securities	3,082	[1]	2,570	[2]	0	[3]
Preferred stock	400	[1]	4,504	[2]	7,258	[3]
Real estate	0	[1]	0	[2]	0	[3]
Mortgage loans	4,203	[1]	6,267	[2]	25,448	[3]
Net cash used by investing activities	(20,838)	[1]	(24,928)	[2]	(10,198)	[3]
Cash flow from financing activities:
Borrowings from credit facilities	0	[1]	0	[2]	0	[3]
Principal repayments on credit facilities	0	[1]	0	[2]	0	[3]
Debt issuance costs	0	[1]	0	[2]	0	[3]
Capital lease payments	0	[1]	0	[2]	0	[3]
Leveraged Employee Stock Ownership Plan	0	[1]	0	[2]	0	[3]
Securitization deposits			0	[2]	0	[3]
Proceeds from (repayment of) intercompany loans	0	[1]	0	[2]	0	[3]
Common stock dividends paid	0	[1]	0	[2]	0	[3]
Contribution to related party			0	[2]	1,500	[3]
Investment contract deposits	0	[1]	0	[2]	0	[3]
Investment contract withdrawals	0	[1]	0	[2]	0	[3]
Net cash provided by financing activities	0	[1]	0	[2]	1,500	[3]
Effects of exchange rate on cash	0	[1]	0	[2]	0	[3]
Increase (decrease) in cash and cash equivalents	(4,263)	[1]	(1,362)	[2]	(8,422)	[3]
Cash and cash equivalents at the beginning of period	12,758	[7]	14,120	[2]	22,542	[3]
Cash and cash equivalents at the end of the period	8,495	[8]	12,758	[7]	14,120	[2]
Operating Segments [Member] | Life Insurance [Member]
Cash flow from operating activities:
Net earnings	19,366	[1]	17,330	[2]	14,985	[3]
Earnings from consolidated subsidiaries	0	[1]	0	[2]	0	[3]
Adjustments to reconcile net earnings to cash provided by operations:
Depreciation	0	[1]	0	[2]	0	[3]
Amortization of deferred policy acquisition costs	19,661	[4]	19,982	[5]	17,376	[6]
Change in allowance for losses on trade receivables	11	[1]	(8)	[2]	0	[3]
Change in allowance for inventory reserves	0	[1]	0	[2]	0	[3]
Net gain on sale of real and personal property	0	[1]	0	[2]	0	[3]
Net (gain) loss on sale of investments	(3,084)	[1]	(4,550)	[2]	(3,364)	[3]
Deferred income taxes	1,842	[1]	4,465	[2]	(147)	[3]
Net change in other operating assets and liabilities:
Reinsurance recoverables and trade receivables	(3,985)	[1]	4,503	[2]	(2,857)	[3]
Inventories	0	[1]	0	[2]	0	[3]
Prepaid expenses	0	[1]	0	[2]	0	[3]
Capitalization of deferred policy acquisition costs	(27,084)	[1]	(32,611)	[2]	(50,640)	[3]
Other assets	(804)	[1]	(222)	[2]	46	[3]
Related party assets	0	[1]	0	[2]	0	[3]
Accounts payable and accrued expenses	7,446	[1]	3,909	[2]	(1,298)	[3]
Policy benefits and losses, claims and loss expenses payable	10,178	[1]	12,674	[2]	21,175	[3]
Other policyholders' funds and liabilities	671	[1]	118	[2]	302	[3]
Deferred income	0	[1]	0	[2]	0	[3]
Related party liabilities	(67)	[1]	(61)	[2]	36	[3]
Net cash provided by operating activities	24,151	[1]	25,529	[2]	(4,386)	[3]
Cash flow from investing activities:
Property, plant and equipment	0	[1]	0	[2]	0	[3]
Short term investments	(249,796)	[1]	(210,139)	[2]	(314,369)	[3]
Fixed maturities investments	(171,309)	[1]	(223,634)	[2]	(398,802)	[3]
Equity securities	(426)	[1]	(816)	[2]	0	[3]
Preferred stock	(1,000)	[1]	0	[2]	0	[3]
Real estate	(7,542)	[1]	(532)	[2]	(830)	[3]
Mortgage loans	(15,457)	[1]	(39,159)	[2]	(33,684)	[3]
Proceeds from sale and paydowns of:
Property, plant and equipment	0	[1]	0	[2]	0	[3]
Short term investments	234,771	[1]	200,200	[2]	329,782	[3]
Fixed maturities investments	89,311	[1]	121,295	[2]	125,313	[3]
Equity securities	0	[1]	0	[2]	0	[3]
Preferred stock	2,027	[1]	1,500	[2]	0	[3]
Real estate	396	[1]	351	[2]	4	[3]
Mortgage loans	9,691	[1]	15,049	[2]	23,798	[3]
Net cash used by investing activities	(109,334)	[1]	(135,885)	[2]	(268,788)	[3]
Cash flow from financing activities:
Borrowings from credit facilities	0	[1]	0	[2]	0	[3]
Principal repayments on credit facilities	0	[1]	0	[2]	0	[3]
Debt issuance costs	0	[1]	0	[2]	0	[3]
Capital lease payments	0	[1]	0	[2]	0	[3]
Leveraged Employee Stock Ownership Plan	0	[1]	0	[2]	0	[3]
Securitization deposits			0	[2]	0	[3]
Proceeds from (repayment of) intercompany loans	0	[1]	0	[2]	0	[3]
Common stock dividends paid	0	[1]	0	[2]	0	[3]
Contribution to related party			0	[2]	0	[3]
Investment contract deposits	123,129	[1]	140,613	[2]	301,729	[3]
Investment contract withdrawals	(54,108)	[1]	(34,677)	[2]	31,901	[3]
Net cash provided by financing activities	69,021	[1]	105,936	[2]	269,828	[3]
Effects of exchange rate on cash	0	[1]	0	[2]	0	[3]
Increase (decrease) in cash and cash equivalents	(16,162)	[1]	(4,420)	[2]	(3,346)	[3]
Cash and cash equivalents at the beginning of period	17,644	[7]	22,064	[2]	25,410	[3]
Cash and cash equivalents at the end of the period	1,482	[8]	17,644	[7]	22,064	[2]
Eliminations [Member]
Cash flow from operating activities:
Net earnings	(34,783)		(29,992)		(24,241)
Earnings from consolidated subsidiaries	34,783		29,992		24,241
Adjustments to reconcile net earnings to cash provided by operations:
Depreciation	0		0		0
Amortization of deferred policy acquisition costs	0		0		0
Change in allowance for losses on trade receivables	0		0		0
Change in allowance for inventory reserves	0		0		0
Net gain on sale of real and personal property	0		0		0
Net (gain) loss on sale of investments	0		0		0
Deferred income taxes	0		0		0
Net change in other operating assets and liabilities:
Reinsurance recoverables and trade receivables	0		0		0
Inventories	0		0		0
Prepaid expenses	0		0		0
Capitalization of deferred policy acquisition costs	0		0		0
Other assets	0		0		0
Related party assets	211	[9]	725	[9]	1,063	[9]
Accounts payable and accrued expenses	0		0		0
Policy benefits and losses, claims and loss expenses payable	0		0		0
Other policyholders' funds and liabilities	0		0		0
Deferred income	0		0		0
Related party liabilities	(211)	[9]	(725)	[9]	(1,063)	[9]
Net cash provided by operating activities	0		0		0
Cash flow from investing activities:
Property, plant and equipment	0		0		0
Short term investments	0		0		0
Fixed maturities investments	0		0		0
Equity securities	0		0		0
Preferred stock	0		0		0
Real estate	0		0		0
Mortgage loans	0		11,589	[9]	0
Proceeds from sale and paydowns of:
Property, plant and equipment	0		0		0
Short term investments	0		0		0
Fixed maturities investments	0		0		0
Equity securities	0		0		0
Preferred stock	0		0		0
Real estate	0		0		0
Mortgage loans	0		(11,589)	[9]	0
Net cash used by investing activities	0		0		0
Cash flow from financing activities:
Borrowings from credit facilities	0		0		0
Principal repayments on credit facilities	0		0		0
Debt issuance costs	0		0		0
Capital lease payments	0		0		0
Leveraged Employee Stock Ownership Plan	0		0		0
Securitization deposits			0		0
Proceeds from (repayment of) intercompany loans	0		0		0
Common stock dividends paid	0		0		0
Contribution to related party			0		0
Investment contract deposits	0		0		0
Investment contract withdrawals	0		0		0
Net cash provided by financing activities	0		0		0
Effects of exchange rate on cash	0		0		0
Increase (decrease) in cash and cash equivalents	0		0		0
Cash and cash equivalents at the beginning of period	0		0		0
Cash and cash equivalents at the end of the period	$ 0		$ 0		$ 0

[1] Balance for the period ended December 31, 2014

[2] Balance for the period ended December 31, 2013

[3] Balance for the period ended December 31, 2012

[4] Balances for the year ended December 31, 2014

[5] Balances for the year ended December 31, 2013

[6] Balances for the year ended December 31, 2012

[7] Balances as of December 31, 2013

[8] Balances as of December 31, 2014

[9] Eliminate intercompany investments