Investments (Table Text Block)

9 Months Ended

Dec. 31, 2018

Investments Debt Equity Securities [Abstract]

Available-for-Sale Investments

Available-for-sale investments as of December 31, 2018 were as follows:

		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses More than 12 Months		Gross Unrealized Losses Less than 12 Months		Estimated Market Value
		(Unaudited)
		(In thousands)
U.S. treasury securities and government obligations	$	128,934	$	1,140	$	(2,319)	$	(2,462)	$	125,293
U.S. government agency mortgage-backed securities		61,243		526		(44)		(1,558)		60,167
Obligations of states and political subdivisions		238,243		5,203		(251)		(2,456)		240,739
Corporate securities		1,576,170		14,898		(8,033)		(26,956)		1,556,079
Mortgage-backed securities		119,006		541		(212)		(1,384)		117,951
Redeemable preferred stocks		1,493		37		–		(20)		1,510
	$	2,125,089	$	22,345	$	(10,859)	$	(34,836)	$	2,101,739

Available-for-sale investments as of March 31, 2018 were as follows:

		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses More than 12 Months		Gross Unrealized Losses Less than 12 Months		Estimated Market Value
		(In thousands)
U.S. treasury securities and government obligations	$	123,557	$	3,595	$	(1,036)	$	(203)	$	125,913
U.S. government agency mortgage-backed securities		36,416		951		(1)		(93)		37,273
Obligations of states and political subdivisions		178,702		9,938		(217)		(18)		188,405
Corporate securities		1,388,300		50,056		(3,009)		(1,826)		1,433,521
Mortgage-backed securities		94,106		2,072		–		(153)		96,025
Preferred stocks		10,609		321		(29)		(40)		10,861
Common stocks		15,732		12,329		(10)		(189)		27,862
	$	1,847,422	$	79,262	$	(4,302)	$	(2,522)	$	1,919,860

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

		December 31, 2018				March 31, 2018
		Amortized Cost		Estimated Market Value		Amortized Cost		Estimated Market Value
		(Unaudited)
		(In thousands)
Due in one year or less	$	58,311	$	58,532	$	36,446	$	36,674
Due after one year through five years		503,227		502,343		441,223		450,816
Due after five years through ten years		648,241		639,629		607,895		626,174
Due after ten years		794,811		781,774		641,411		671,448
		2,004,590		1,982,278		1,726,975		1,785,112
Mortgage-backed securities		119,006		117,951		94,106		96,025
Redeemable preferred stocks		1,493		1,510		2,118		2,247
Equity securities		–		–		24,223		36,476
	$	2,125,089	$	2,101,739	$	1,847,422	$	1,919,860

Available for sale equity investments

		Estimated Market Value as of
		December 31, 2018
		(Unaudited)
		(In thousands)
Common stocks	$	18,298
Non-redeemable preferred stocks		7,305
	$	25,603