Investments (Table Text Block)

12 Months Ended

Mar. 31, 2017

Mar. 31, 2016

Investments, Debt and Equity Securities [Abstract]

Available-for-Sale Investments

		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	$	123,474	$	2,892	$	–	$	(1,675)	$	124,691
U.S. government agency mortgage-backed securities		27,908		1,070		(6)		(377)		28,595
Obligations of states and political subdivisions		159,417		9,466		(23)		(424)		168,436
Corporate securities		1,263,703		32,901		(5,731)		(13,837)		1,277,036
Mortgage-backed securities		26,577		515		–		(5)		27,087
Redeemable preferred stocks		13,789		168		–		(468)		13,489
Common stocks		15,732		8,728		(10)		(16)		24,434
	$	1,630,600	$	55,740	$	(5,770)	$	(16,802)	$	1,663,768

		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	$	85,861	$	3,791	$	–	$	(193)	$	89,459
U.S. government agency mortgage-backed securities		21,845		1,596		(6)		(39)		23,396
Obligations of states and political subdivisions		166,725		10,660		(81)		(414)		176,890
Corporate securities		1,143,125		26,861		(8,013)		(28,181)		1,133,792
Mortgage-backed securities		24,991		475		–		(62)		25,404
Redeemable preferred stocks		17,977		556		–		(105)		18,428
Common stocks		15,983		7,822		(10)		(375)		23,420
	$	1,476,507	$	51,761	$	(8,110)	$	(29,369)	$	1,490,789

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

		March 31, 2017				March 31, 2016
		Amortized Cost		Estimated Market Value		Amortized Cost		Estimated Market Value
		(In thousands)
Due in one year or less	$	35,399	$	35,795	$	48,679	$	49,146
Due after one year through five years		324,286		333,016		250,576		256,597
Due after five years through ten years		598,232		607,184		557,984		557,961
Due after ten years		616,585		622,763		560,317		559,833
		1,574,502		1,598,758		1,417,556		1,423,537
Mortgage backed securities		26,577		27,087		24,991		25,404
Redeemable preferred stocks		13,789		13,489		17,977		18,428
Equity securities		15,732		24,434		15,983		23,420
	$	1,630,600	$	1,663,768	$	1,476,507	$	1,490,789

Carrying Value of Other Investments

		March 31,
		2017		2016
		(In thousands)
Mortgage loans, net	$	262,875	$	217,198
Short-term investments		15,149		34,798
Real estate		66,174		34,416
Policy loans		17,112		17,091
Other equity investments		6,520		8,318
	$	367,830	$	311,821