Consolidating financial information by industry segment (Cash Flow Statements) (Details) - USD ($) $ in Thousands		3 Months Ended				6 Months Ended
		Sep. 30, 2016		Sep. 30, 2015		Sep. 30, 2016		Sep. 30, 2015
Cash flow from operating activities:
Net earnings		$ 176,475		$ 183,379		$ 323,648		$ 354,664
Earnings from consolidated entities
Adjustments to reconcile net earnings to cash provided by operations:
Depreciation						233,543		192,865
Amortization of deferred policy acquisition costs		5,989		5,643		13,931		10,421
Amortization of debt issuance costs						1,765		1,512
Interest credited to policyholders						11,028		10,484
Change in allowance for losses on trade receivables						34		(9)
Change in allowance for inventory reserves						800		(603)
Net gain on sale of real and personal property		(9,618)		(32,821)		(28,258)		(78,805)
Net (gain) loss on sale of investments						(4,645)		(3,022)
Deferred income tax						114,724		27,259
Net change in other operating assets and liabilities:
Reinsurance recoverables and trade receivables						(8,102)		13,618
Inventories						(2,674)		(2,107)
Prepaid expenses						46,248		71,813
Capitalization of deferred policy acquisition costs						(14,360)		(15,636)
Other assets						(8,695)		16,794
Related party assets						5,195		57,767
Accounts payable and accrued expenses						45,162		59,525
Policy benefits and losses, claims and loss expenses payable						16,922		11,702
Other policyholders' funds and liabilities						1,563		2,684
Deferred income						5,034		2,339
Related party liabilities						232		(97)
Net cash provided by operating activities						753,095		733,168
Cash flow from investing activities:
Property, plant and equipment						(761,277)		(720,265)
Short term investments						(409,925)		(249,082)
Fixed maturities investments						(168,817)		(169,899)
Equity securities						(489)		(1,315)
Preferred stock								(3)
Real estate						(15,788)		(23)
Mortgage loans						(136,682)		(86,361)
Proceeds from sale of:
Property, plant and equipment						310,409		379,198
Short term investments						386,508		243,634
Fixed maturities investments						120,525		89,085
Equity securities								808
Preferred stock						2,651
Real estate						831
Mortgage loans						105,731		29,895
Net cash used by investing activities						(566,323)		(484,328)
Cash flow from financing activities:
Borrowings from credit facilities						331,787		461,735
Principal repayments on credit facilities						(158,479)		(187,958)
Debt issuance costs						(2,085)		(5,957)
Capital lease payments						(83,414)		(77,786)
Employee Stock Ownership Plan						(4,653)		(1,484)
Securitization deposits						245		298
Common stock dividends paid						(19,586)		(19,594)
Investment contract deposits						130,166		140,220
Investment contract withdrawals						(49,555)		(25,974)
Net cash provided by (used in) financing activities						144,426		283,500
Effects of exchange rate on cash						(10,517)		(12,543)
Increase (decrease) in cash and cash equivalents						320,681		519,797
Cash and cash equivalents at the beginning of period						600,646		441,850
Cash and cash equivalents at the end of the period		921,327		961,647		921,327		961,647
Operating Segments [Member] | Moving and Storage Consolidations [Member]
Cash flow from operating activities:
Net earnings		176,475		183,379		323,648		354,664
Earnings from consolidated entities						(16,879)		(16,129)
Adjustments to reconcile net earnings to cash provided by operations:
Depreciation						233,543		192,865
Amortization of deferred policy acquisition costs
Amortization of debt issuance costs						1,765		1,512
Interest credited to policyholders
Change in allowance for losses on trade receivables						92		(21)
Change in allowance for inventory reserves						800		(603)
Net gain on sale of real and personal property						(28,258)		(78,805)
Net (gain) loss on sale of investments
Deferred income tax						114,112		23,125
Net change in other operating assets and liabilities:
Reinsurance recoverables and trade receivables						(6,265)		1,021
Inventories						(2,674)		(2,107)
Prepaid expenses						46,248		71,813
Capitalization of deferred policy acquisition costs
Other assets						(10,925)		15,609
Related party assets						5,718		58,373
Accounts payable and accrued expenses						41,958		51,340
Policy benefits and losses, claims and loss expenses payable						13,165		20,648
Other policyholders' funds and liabilities
Deferred income						5,034		2,339
Related party liabilities						(170)		(26)
Net cash provided by operating activities						720,912		695,618
Cash flow from investing activities:
Property, plant and equipment						(761,277)		(720,265)
Short term investments
Fixed maturities investments
Equity securities
Preferred stock
Real estate						(3,510)
Mortgage loans						(1,982)		(11,748)
Proceeds from sale of:
Property, plant and equipment						310,409		379,198
Short term investments
Fixed maturities investments
Equity securities
Preferred stock
Real estate
Mortgage loans						4,345		10,011
Net cash used by investing activities						(452,015)		(342,804)
Cash flow from financing activities:
Borrowings from credit facilities						304,787		414,735
Principal repayments on credit facilities						(131,479)		(140,958)
Debt issuance costs						(2,085)		(5,957)
Capital lease payments						(83,414)		(77,786)
Employee Stock Ownership Plan						(4,653)		(1,484)
Securitization deposits						245		298
Common stock dividends paid						(19,586)		(19,594)
Investment contract deposits
Investment contract withdrawals
Net cash provided by (used in) financing activities						63,815		169,254
Effects of exchange rate on cash						(10,517)		(12,543)
Increase (decrease) in cash and cash equivalents						322,195		509,525
Cash and cash equivalents at the beginning of period						585,666		431,873
Cash and cash equivalents at the end of the period		907,861		941,398		907,861		941,398
Operating Segments [Member] | Property and Casualty Insurance [Member]
Cash flow from operating activities:
Net earnings		4,688	[1]	3,942	[2]	9,565	[3]	8,153	[4]
Earnings from consolidated entities							[3]		[4]
Adjustments to reconcile net earnings to cash provided by operations:
Depreciation							[3]		[4]
Amortization of deferred policy acquisition costs			[1]		[2]		[5]		[6]
Amortization of debt issuance costs							[3]		[4]
Interest credited to policyholders							[3]		[4]
Change in allowance for losses on trade receivables							[3]		[4]
Change in allowance for inventory reserves							[3]		[4]
Net gain on sale of real and personal property							[3]		[4]
Net (gain) loss on sale of investments						(2,709)	[3]	(810)	[4]
Deferred income tax						24	[3]	3,127	[4]
Net change in other operating assets and liabilities:
Reinsurance recoverables and trade receivables						429	[3]	8,827	[4]
Inventories							[3]		[4]
Prepaid expenses							[3]		[4]
Capitalization of deferred policy acquisition costs							[3]		[4]
Other assets						2,150	[3]	1,097	[4]
Related party assets						(523)	[3]	(606)	[4]
Accounts payable and accrued expenses						1,766	[3]	1,243	[4]
Policy benefits and losses, claims and loss expenses payable						(2,888)	[3]	(13,336)	[4]
Other policyholders' funds and liabilities						566	[3]	(1,308)	[4]
Deferred income							[3]		[4]
Related party liabilities						456	[3]	(75)	[4]
Net cash provided by operating activities						8,836	[3]	6,312	[4]
Cash flow from investing activities:
Property, plant and equipment							[3]		[4]
Short term investments						(36,646)	[3]	(19,247)	[4]
Fixed maturities investments						(13,469)	[3]	(20,286)	[4]
Equity securities							[3]		[4]
Preferred stock	[4]							(3)
Real estate						(4,580)	[3]	(6)	[4]
Mortgage loans						(3,063)	[3]		[4]
Proceeds from sale of:
Property, plant and equipment							[3]		[4]
Short term investments						17,771	[3]	20,865	[4]
Fixed maturities investments						16,623	[3]	12,783	[4]
Equity securities	[4]
Preferred stock	[3]					2,651
Real estate	[3]
Mortgage loans						9,603	[3]	4,253	[4]
Net cash used by investing activities						(11,110)	[3]	(1,641)	[4]
Cash flow from financing activities:
Borrowings from credit facilities							[3]		[4]
Principal repayments on credit facilities							[3]		[4]
Debt issuance costs							[3]		[4]
Capital lease payments							[3]		[4]
Employee Stock Ownership Plan							[3]		[4]
Securitization deposits							[3]		[4]
Common stock dividends paid							[3]		[4]
Investment contract deposits							[3]		[4]
Investment contract withdrawals							[3]		[4]
Net cash provided by (used in) financing activities							[3]		[4]
Effects of exchange rate on cash							[3]		[4]
Increase (decrease) in cash and cash equivalents						(2,274)	[3]	4,671	[4]
Cash and cash equivalents at the beginning of period						14,049	[7]	8,495	[4]
Cash and cash equivalents at the end of the period		11,775	[8]	13,166	[4]	11,775	[8]	13,166	[4]
Operating Segments [Member] | Life Insurance [Member]
Cash flow from operating activities:
Net earnings		4,617	[1]	5,237	[2]	7,314	[3]	7,976	[4]
Earnings from consolidated entities							[3]		[4]
Adjustments to reconcile net earnings to cash provided by operations:
Depreciation							[3]		[4]
Amortization of deferred policy acquisition costs		5,989	[1]	5,643	[2]	13,931	[5]	10,421	[6]
Amortization of debt issuance costs							[3]		[4]
Interest credited to policyholders						11,028	[3]	10,484	[4]
Change in allowance for losses on trade receivables						(58)	[3]	12	[4]
Change in allowance for inventory reserves							[3]		[4]
Net gain on sale of real and personal property							[3]		[4]
Net (gain) loss on sale of investments						(1,936)	[3]	(2,212)	[4]
Deferred income tax						588	[3]	1,007	[4]
Net change in other operating assets and liabilities:
Reinsurance recoverables and trade receivables						(2,266)	[3]	3,770	[4]
Inventories							[3]		[4]
Prepaid expenses							[3]		[4]
Capitalization of deferred policy acquisition costs						(14,360)	[3]	(15,636)	[4]
Other assets						80	[3]	88	[4]
Related party assets							[3]		[4]
Accounts payable and accrued expenses						1,438	[3]	6,942	[4]
Policy benefits and losses, claims and loss expenses payable						6,645	[3]	4,390	[4]
Other policyholders' funds and liabilities						997	[3]	3,992	[4]
Deferred income							[3]		[4]
Related party liabilities						(54)	[3]	4	[4]
Net cash provided by operating activities						23,347	[3]	31,238	[4]
Cash flow from investing activities:
Property, plant and equipment							[3]		[4]
Short term investments						(373,279)	[3]	(229,835)	[4]
Fixed maturities investments						(155,348)	[3]	(149,613)	[4]
Equity securities						(489)	[3]	(1,315)	[4]
Preferred stock	[4]
Real estate						(7,698)	[3]	(17)	[4]
Mortgage loans						(131,637)	[3]	(74,613)	[4]
Proceeds from sale of:
Property, plant and equipment							[3]		[4]
Short term investments						368,737	[3]	222,769	[4]
Fixed maturities investments						103,902	[3]	76,302	[4]
Equity securities	[4]							808
Preferred stock	[3]
Real estate	[3]					831
Mortgage loans						91,783	[3]	15,631	[4]
Net cash used by investing activities						(103,198)	[3]	(139,883)	[4]
Cash flow from financing activities:
Borrowings from credit facilities						27,000	[3]	47,000	[4]
Principal repayments on credit facilities						(27,000)	[3]	(47,000)	[4]
Debt issuance costs							[3]		[4]
Capital lease payments							[3]		[4]
Employee Stock Ownership Plan							[3]		[4]
Securitization deposits							[3]		[4]
Common stock dividends paid							[3]		[4]
Investment contract deposits						130,166	[3]	140,220	[4]
Investment contract withdrawals						(49,555)	[3]	(25,974)	[4]
Net cash provided by (used in) financing activities						80,611	[3]	114,246	[4]
Effects of exchange rate on cash							[3]		[4]
Increase (decrease) in cash and cash equivalents						760	[3]	5,601	[4]
Cash and cash equivalents at the beginning of period						931	[7]	1,482	[4]
Cash and cash equivalents at the end of the period		1,691	[8]	7,083	[4]	1,691	[8]	7,083	[4]
Consolidation, Eliminations [Member]
Cash flow from operating activities:
Net earnings		(9,305)		(9,179)		(16,879)		(16,129)
Earnings from consolidated entities						16,879		16,129
Adjustments to reconcile net earnings to cash provided by operations:
Depreciation
Amortization of deferred policy acquisition costs
Amortization of debt issuance costs
Interest credited to policyholders
Change in allowance for losses on trade receivables
Change in allowance for inventory reserves
Net gain on sale of real and personal property
Net (gain) loss on sale of investments
Deferred income tax
Net change in other operating assets and liabilities:
Reinsurance recoverables and trade receivables
Inventories
Prepaid expenses
Capitalization of deferred policy acquisition costs
Other assets
Related party assets
Accounts payable and accrued expenses
Policy benefits and losses, claims and loss expenses payable
Other policyholders' funds and liabilities
Deferred income
Related party liabilities
Net cash provided by operating activities
Cash flow from investing activities:
Property, plant and equipment
Short term investments
Fixed maturities investments
Equity securities
Preferred stock
Real estate
Mortgage loans
Proceeds from sale of:
Property, plant and equipment
Short term investments
Fixed maturities investments
Equity securities
Preferred stock
Real estate
Mortgage loans
Net cash used by investing activities
Cash flow from financing activities:
Borrowings from credit facilities
Principal repayments on credit facilities
Debt issuance costs
Capital lease payments
Employee Stock Ownership Plan
Securitization deposits
Common stock dividends paid
Investment contract deposits
Investment contract withdrawals
Net cash provided by (used in) financing activities
Effects of exchange rate on cash
Increase (decrease) in cash and cash equivalents
Cash and cash equivalents at the beginning of period
Cash and cash equivalents at the end of the period

[1] Balances for the quarter ended June 30, 2016

[2] Balances for the quarter ended June 30, 2015

[3] Balance for the period ended June 30, 2016

[4] Balance for the period ended June 30, 2015

[5] Balances for the six months ended June 30, 2016

[6] Balances for the six months ended June 30, 2015

[7] Balances as of December 31, 2015

[8] Balances as of June 30, 2016