Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2019

Fair Value Disclosures [Abstract]

Balances Of Assets Measured At Fair Value On A Recurring Basis

The following tables present the balances of assets measured at fair value on a recurring basis by level within the fair value hierarchy.

	March 31, 2019
(dollars in thousands)	Level 1		Level 2		Level 3		Total
Assets:
Investments:
Fixed maturities, available-for-sale:
U.S. Treasury securities	$	—	$	272,772	$	—	$	272,772
U.S. government-sponsored enterprises	—		367,320		—		367,320
Obligations of states, municipalities and political subdivisions	—		4,356,853		—		4,356,853
Foreign governments	—		1,606,899		—		1,606,899
Commercial mortgage-backed securities	—		1,683,611		—		1,683,611
Residential mortgage-backed securities	—		889,877		—		889,877
Asset-backed securities	—		13,089		—		13,089
Corporate bonds	—		971,998		—		971,998
Total fixed maturities, available-for-sale	—		10,162,419		—		10,162,419
Equity securities:
Insurance, banks and other financial institutions	2,053,233		—		44,812		2,098,045
Industrial, consumer and all other	4,283,128		—		—		4,283,128
Total equity securities	6,336,361		—		44,812		6,381,173
Short-term investments, available-for-sale	646,853		107,435		—		754,288
Total investments	$	6,983,214	$	10,269,854	$	44,812	$	17,297,880

	December 31, 2018
(dollars in thousands)	Level 1		Level 2		Level 3		Total
Assets:
Investments:
Fixed maturities, available-for-sale:
U.S. Treasury securities	$	—	$	246,642	$	—	$	246,642
U.S. government-sponsored enterprises	—		359,322		—		359,322
Obligations of states, municipalities and political subdivisions	—		4,352,930		—		4,352,930
Foreign governments	—		1,559,604		—		1,559,604
Commercial mortgage-backed securities	—		1,650,199		—		1,650,199
Residential mortgage-backed securities	—		880,172		—		880,172
Asset-backed securities	—		19,408		—		19,408
Corporate bonds	—		974,911		—		974,911
Total fixed maturities	—		10,043,188		—		10,043,188
Equity securities:
Insurance, banks and other financial institutions	1,876,811		—		53,728		1,930,539
Industrial, consumer and all other	3,790,406		—		—		3,790,406
Total equity securities	5,667,217		—		53,728		5,720,945
Short-term investments, available-for-sale	981,616		96,080		—		1,077,696
Total investments	$	6,648,833	$	10,139,268	$	53,728	$	16,841,829

Summary Of Changes In Level 3 Investments Measured At Fair Value On A Recurring Basis

The following table summarizes changes in Level 3 investments measured at fair value on a recurring basis.

	Three Months Ended March 31,
(dollars in thousands)	2019			2018
Equity securities, beginning of period	$	53,728		$	168,809
Purchases	—			28,900
Sales	(6,869		)	(28,252		)
Net investment losses on Level 3 investments	(2,047		)	(18,059		)
Transfers into Level 3	—			—
Transfers out of Level 3	—			—
Equity securities, end of period	$	44,812		$	151,398