Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2018

Fair Value Disclosures [Abstract]

Assets And Liabilities Measured At Fair value, On A Recurring Basis

The following tables present the assets and liabilities measured at fair value on a recurring basis as of March 31, 2018 and December 31, 2017 by level:

(In thousands)	Total		Level 1		Level 2		Level 3
March 31, 2018
Assets:
Fixed maturity securities available for sale:
U.S. government and government agency	$	479,909	$	—	$	479,909	$	—
State and municipal	4,311,524		—		4,311,524		—
Mortgage-backed securities	1,386,997		—		1,386,997		—
Asset-backed securities	2,101,691		—		2,101,528		163
Corporate	4,110,701		—		4,110,701		—
Foreign government	873,079		—		873,079		—
Total fixed maturity securities available for sale	13,263,901		—		13,263,738		163
Equity securities:
Common stocks	320,435		311,329		—		9,106
Preferred stocks	175,599		—		164,756		10,843
Total equity securities	496,034		311,329		164,756		19,949
Arbitrage trading account	744,859		434,470		306,547		3,842
Total	$	14,504,794	$	745,799	$	13,735,041	$	23,954
Liabilities:
Trading account securities sold but not yet purchased	$	29,453	$	29,444	$	9	$	—
December 31, 2017
Assets:
Fixed maturity securities available for sale:
U.S. government and government agency	$	377,740	$	—	$	377,740	$	—
State and municipal	4,445,094		—		4,445,094		—
Mortgage-backed securities	1,299,931		—		1,299,931		—
Asset-backed securities	2,111,544		—		2,111,372		172
Corporate	4,389,112		—		4,389,112		—
Foreign government	848,497		—		848,497		—
Total fixed maturity securities available for sale	13,471,918		—		13,471,746		172
Equity securities:
Common stocks	352,204		342,834		—		9,370
Preferred stocks	224,443		—		213,600		10,843
Total equity securities	576,647		342,834		213,600		20,213
Arbitrage trading account	617,649		471,420		146,229		—
Total	$	14,666,214	$	814,254	$	13,831,575	$	20,385
Liabilities:
Trading account securities sold but not yet purchased	$	64,358	$	64,358	$	—	$	—

Summarize Changes In Level 3 Assets

The following tables summarize changes in Level 3 assets and liabilities for the three months ended March 31, 2018 and for the year ended December 31, 2017:

	Gains (Losses) Included in:
(In thousands)	Beginning Balance		Earnings (Losses)			Other Comprehensive Income (Loss)		Impairments		Purchases		(Sales)			Paydowns / Maturities		Transfers		Ending Balance
																	In / (Out)
Three Months Ended March 31, 2018
Assets:
Fixed maturities securities available for sale:
Asset-backed securities	$	172	$	2		$	4	$	—	$	—	$	(15	)	$	—	$	—	$	163
Total	172		2			4		—		—		(15		)	—		—		163
Equity securities:
Common stocks	9,370		(264		)	—		—		—		—			—		—		9,106
Preferred stocks	10,843		—			—		—		—		—			—		—		10,843
Total	20,213		(264		)	—		—		—		—			—		—		19,949
Arbitrage trading account	—		(40		)	—		—		3,882		—			—		—		3,842
Total	$	20,385	$	(302	)	$	4	$	—	$	3,882	$	(15	)	$	—	$	—	$	23,954
Year ended December 31, 2017
Assets:
Fixed maturities securities available for sale:
Asset-backed securities	$	183	$	3		$	34	$	—	$	—	$	(48	)	$	—	$	—	$	172
Total	183		3			34		—		—		(48		)	—		—		172
Equity securities:
Common stocks	8,754		—			616		—		—		—			—		—		9,370
Preferred stocks	3,662		8			—		—		7,173		—			—		—		10,843
Total	12,416		8			616		—		7,173		—			—		—		20,213
Arbitrage trading account	—		8			—		—		—		(8		)	—		—		—
Total	$	12,599	$	19		$	650	$	—	$	7,173	$	(56	)	$	—	$	—	$	20,385