Investments (Table Text Block)

3 Months Ended

12 Months Ended

Jun. 30, 2024

Mar. 31, 2024

Investments Debt Equity Securities [Abstract]

Available for sale investments

Available-for-sale investments as of June 30, 2024 were as follows:

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Allowance for Expected Credit Losses			Fair Value
	(Unaudited)
	(In thousands)
U.S. treasury securities and government obligations	$	147,881	$	235	$	(9,361	)	$	—		$	138,755
U.S. government agency mortgage-backed securities		47,208		153		(8,044	)		—			39,317
Obligations of states and political subdivisions		150,396		313		(8,108	)		—			142,601
Corporate securities		1,987,105		1,318		(165,015	)		(2,995	)		1,820,413
Mortgage-backed securities		299,291		33		(44,520	)		—			254,804
	$	2,631,881	$	2,052	$	(235,048	)	$	(2,995	)	$	2,395,890

Available-for-sale investments as of March 31, 2024 were as follows:

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Allowance for Expected Credit Losses			Fair Value
	(In thousands)
U.S. treasury securities and government obligations	$	191,070	$	2,123	$	(8,921	)	$	—		$	184,272
U.S. government agency mortgage-backed securities		48,067		250		(7,664	)		—			40,653
Obligations of states and political subdivisions		151,197		918		(7,533	)		—			144,582
Corporate securities		1,963,249		2,762		(152,799	)		(1,052	)		1,812,160
Mortgage-backed securities		306,510		34		(45,707	)		—			260,837
	$	2,660,093	$	6,087	$	(222,624	)	$	(1,052	)	$	2,442,504

Available for sale investments, unrealized losses, fair value

	June 30, 2024
	Less than or equal to 1 year					Greater than 1 year					Total
	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
	(Unaudited)
	(In thousands)
U.S. treasury securities and government obligations	$	35,130	$	(40	)	$	99,447	$	(9,321	)	$	134,577	$	(9,361	)
U.S. government agency mortgage-backed securities		—		—			22,893		(8,044	)		22,893		(8,044	)
Obligations of states and political subdivisions		31,299		(489	)		81,171		(7,619	)		112,470		(8,108	)
Corporate securities		204,656		(1,729	)		1,500,739		(163,286	)		1,705,395		(165,015	)
Mortgage-backed securities		10,340		(43	)		242,491		(44,477	)		252,831		(44,520	)
	$	281,425	$	(2,301	)	$	1,946,741	$	(232,747	)	$	2,228,166	$	(235,048	)

	March 31, 2024
	Less than or equal to 1 year					Greater than 1 year					Total
	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
	(Unaudited)
	(In thousands)
U.S. treasury securities and government obligations	$	1,888	$	(13	)	$	103,336	$	(8,908	)	$	105,224	$	(8,921	)
U.S. government agency mortgage-backed securities		—		—			23,711		(7,664	)		23,711		(7,664	)
Obligations of states and political subdivisions		10,492		(222	)		80,082		(7,311	)		90,574		(7,533	)
Corporate securities		132,513		(1,258	)		1,495,167		(151,541	)		1,627,680		(152,799	)
Mortgage-backed securities		3,008		(23	)		248,423		(45,684	)		251,431		(45,707	)
	$	147,901	$	(1,516	)	$	1,950,719	$	(221,108	)	$	2,098,620	$	(222,624	)

Adjusted Cost and Estimated Market Value of Available-for-sale Investments

	June 30, 2024				March 31, 2024
	Amortized Cost		Fair Value		Amortized Cost		Fair Value
	(Unaudited)
	(In thousands)
Due in one year or less	$	301,514	$	299,952	$	266,357	$	266,578
Due after one year through five years		608,709		587,286		748,338		723,903
Due after five years through ten years		664,240		605,525		614,890		564,422
Due after ten years		758,127		648,323		723,998		626,764
		2,332,590		2,141,086		2,353,583		2,181,667
Mortgage-backed securities		299,291		254,804		306,510		260,837
	$	2,631,881	$	2,395,890	$	2,660,093	$	2,442,504

Available for sale equity investments

Equity investments of common stock and non-redeemable preferred stock were as follows:

	June 30, 2024				March 31, 2024
	Amortized Cost		Fair Value		Amortized Cost		Fair Value
	(Unaudited)
	(In thousands)
Common stocks	$	35,284	$	51,999	$	29,604	$	45,014
Non-redeemable preferred stocks		25,144		22,067		25,144		21,260
	$	60,428	$	74,066	$	54,748	$	66,274

Carrying value of Investments, other

The carrying value of the other investments was as follows:

	June 30,		March 31,
	2024		2024
	(Unaudited)
	(In thousands)
Mortgage loans, net	$	617,230	$	604,481
Short-term investments		—		997
Policy loans		11,390		11,229
Other investments		9,803		17,229
	$	638,423	$	633,936