Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Cash flow from operating activities:
Net earnings	$ 610,856	$ 442,048	$ 370,857
Adjustments to reconcile net earnings to cash provided by operations:
Depreciation	664,001	664,120	581,025
Amortization of deferred policy acquisition costs	28,293	31,219	28,556
Amortization of premiums and accretion of discounts related to investments, net	14,229	13,317	13,107
Amortization of debt issuance costs	5,948	4,426	3,923
Interest credited to policyholders	55,321	51,857	35,387
Change in allowance for losses on trade receivables	1,206	(14)	52
Change in allowance for inventory reserves	1,298	640	(146)
Net gains on disposal of personal property	(54,071)	(27,057)	(26,982)
Net gains on disposal of real estate	3,281	(758)	(44)
Net gains on sales of investments	(10,058)	(13,596)	(2,663)
Net losses on equity investments	(394)	(3,783)	5,739
Deferred income taxes	68,411	317,893	106,811
Net change in other operating assets and liabilities:
Reinsurance recoverables and trade receivables	(39,516)	38,129	(31,365)
Inventories and parts	(5,775)	1,776	(13,492)
Prepaid expenses	94,359	(391,120)	(8,620)
Capitalization of deferred policy acquisition costs	(36,162)	(24,447)	(25,957)
Other assets	29,865	(1,295)	157,152
Related party assets	(487)	(5,645)	4,194
Accounts payable and accrued expenses	92,925	(4,530)	10,263
Policy benefits and losses, claims and loss expenses payable	(1,992)	(12,618)	(236,120)
Other policyholders' funds and liabilities	2,230	(4,857)	5,007
Deferred income	11,567	(1,818)	966
Related party liabilities	60	1,626	(2,067)
Net cash provided by operating activities	1,535,395	1,075,513	975,583
Cash flow from investing activities:
Escrow deposits	(5,221)	6,617	4,299
Purchase of:
Property, plant and equipment	(1,441,475)	(2,309,406)	(1,869,968)
Short term investments	(69,929)	(61,226)	(54,048)
Fixed maturities investments	(606,233)	(379,349)	(540,045)
Equity securities	(962)	(83)	(957)
Preferred stock	(16,144)	0	0
Real estate	(622)	(4,286)	(635)
Mortgage loans	(158,071)	(62,016)	(63,611)
Proceeds from sale and paydowns of:
Property, plant and equipment	537,484	687,375	606,271
Short term investments	69,718	59,056	66,037
Fixed maturities investments	529,239	268,636	123,551
Equity securities	207	185	8,608
Preferred stock	2,700	2,375	1,625
Real estate	255	311	0
Mortgage loans	29,525	25,162	147,737
Net cash used by investing activities	(1,129,529)	(1,766,649)	(1,571,136)
Cash flow from financing activities:
Borrowings from credit facilities	922,008	1,121,412	897,311
Principal repayments on credit facilities	(662,588)	(349,986)	(299,748)
Debt issuance costs	(5,793)	(5,332)	(7,243)
Capital lease payments	(221,247)	(307,782)	(303,431)
Employee stock ownership plan shares	0	(206)	(418)
Common stock dividends paid	(49,019)	(29,404)	(39,179)
Investment contract deposits	517,856	234,640	400,123
Investment contract withdrawals	(213,864)	(151,022)	(132,833)
Net cash provided by financing activities	287,353	512,320	514,582
Effects of exchange rate on cash	6,441	(533)	(4,716)
Increase (decrease) in cash and cash equivalents	699,660	(179,349)	(85,687)
Cash and cash equivalents at the beginning of period	494,352	673,701	759,388
Cash and cash equivalents at the end of the period	$ 1,194,012	$ 494,352	$ 673,701