Investments (Tables)

3 Months Ended

Mar. 31, 2021

Investments Debt And Equity Securities [Abstract]

Schedule of Disposition of Fixed Income and Equity Securities

Sales	Proceeds		Gross Realized					Net Realized
(in thousands)	From Sales		Gains		Losses			Gain (Loss)
2021
Available-for-sale	$	21,273	$	1,003	$	(27	)	$	976
Equities		47,638		14,233		(1,150	)		13,083
2020
Available-for-sale	$	19,858	$	2,270	$	(102	)	$	2,168
Equities		38,042		17,792		(2,633	)		15,159

Calls/Maturities			Gross Realized					Net Realized
(in thousands)	Proceeds		Gains		Losses			Gain (Loss)
2021
Available-for-sale	$	96,285	$	255	$	(48	)	$	207
2020
Available-for-sale	$	54,890	$	145	$	(7	)	$	138

Fair Value, Assets Measured on Recurring Basis

Assets measured at fair value on a recurring basis as of March 31, 2021 and December 31, 2020 are summarized below:

	As of March 31, 2021
	Fair Value Measurements Using
		Quoted Prices in		Significant Other		Significant
		Active Markets for		Observable		Unobservable
		Identical Assets		Inputs		Inputs
(in thousands)		(Level 1)		(Level 2)		(Level 3)		Total
Fixed income securities - available-for-sale
U.S. government		$	—	$	170,422	$	—	$	170,422
U.S. agency			—		31,666		—		31,666
Non-U.S. government & agency			—		8,555		—		8,555
Agency MBS			—		369,212		—		369,212
ABS/CMBS/MBS*			—		218,232		—		218,232
Corporate			—		810,751		22,452		833,203
Municipal			—		544,579		—		544,579
Total fixed income securities - available-for-sale		$	—	$	2,153,417	$	22,452	$	2,175,869
Equity securities			555,105		104		—		555,209
Other invested assets			—		—		—		—
Total		$	555,105	$	2,153,521	$	22,452	$	2,731,078

* Non-agency asset-backed, commercial mortgage-backed and mortgage-backed securities

	As of December 31, 2020
	Fair Value Measurements Using
		Quoted Prices in		Significant Other		Significant
		Active Markets for		Observable		Unobservable
		Identical Assets		Inputs		Inputs
(in thousands)		(Level 1)		(Level 2)		(Level 3)		Total
Fixed income securities - available-for-sale
U.S. government		$	—	$	183,357	$	—	$	183,357
U.S. agency			—		32,872		—		32,872
Non-U.S. government & agency			—		10,965		—		10,965
Agency MBS			—		402,071		—		402,071
ABS/CMBS/MBS*			—		218,373		—		218,373
Corporate			—		798,794		17,798		816,592
Municipal			—		532,396		—		532,396
Total fixed income securities - available-for-sale		$	—	$	2,178,828	$	17,798	$	2,196,626
Equity securities			523,923		83		—		524,006
Other invested assets			6,068		—		—		6,068
Total		$	529,991	$	2,178,911	$	17,798	$	2,726,700

* Non-agency asset-backed, commercial mortgage-backed and mortgage-backed securities

Summary of Changes in Balance of Level 3 Securities

(in thousands)	Level 3 Securities
Balance as of January 1, 2021	$	17,798
Net realized and unrealized gains (losses)
Included in net earnings as a part of:
Net investment income		(13	)
Net realized gains		(192	)
Included in other comprehensive earnings (loss)		(606	)
Total net realized and unrealized gains (losses)	$	(811	)
Purchases		5,465
Balance as of March 31, 2021	$	22,452
Change in unrealized gains (losses) during the period for Level 3 assets held at period-end - included in net realized gains	$	(192	)
Change in unrealized gains (losses) during the period for Level 3 assets held at period-end - included in other comprehensive earnings	$	(606	)

Schedule of Contractual Maturity of Securities

	March 31, 2021
(in thousands)	Amortized Cost		Fair Value
Due in one year or less	$	105,159	$	106,340
Due after one year through five years		512,686		539,027
Due after five years through 10 years		522,850		552,085
Due after 10 years		382,756		390,973
ABS/CMBS/MBS*		573,401		587,444
Total available-for-sale	$	2,096,852	$	2,175,869

* Asset-backed, commercial mortgage-backed and mortgage-backed securities

Schedule of Amortized Cost and Fair Value of Available-for-sale Securities

The amortized cost and fair value of available-for-sale securities at March 31, 2021 and December 31, 2020 are presented in the tables below. Amortized cost does not include the $14.9 million of accrued interest receivable as of March 31, 2021 and December 31, 2020.

	March 31, 2021
	Cost or		Allowance			Gross		Gross
	Amortized		for Credit			Unrealized		Unrealized			Fair
(in thousands)	Cost		Losses			Gains		Losses			Value
U.S. government	$	161,956	$	—		$	9,539	$	(1,073	)	$	170,422
U.S. agency		28,883		—			2,783		—			31,666
Non-U.S. government & agency		8,296		—			407		(148	)		8,555
Agency MBS		358,224		—			14,007		(3,019	)		369,212
ABS/CMBS/MBS*		215,177		—			3,713		(658	)		218,232
Corporate		796,042		(375	)		42,200		(4,664	)		833,203
Municipal		528,274		—			21,781		(5,476	)		544,579
Total Fixed Income	$	2,096,852	$	(375	)	$	94,430	$	(15,038	)	$	2,175,869

	December 31, 2020
	Cost or		Allowance			Gross		Gross
	Amortized		for Credit			Unrealized		Unrealized			Fair
(in thousands)	Cost		Losses			Gains		Losses			Value
U.S. government	$	170,110	$	—		$	13,504	$	(257	)	$	183,357
U.S. agency		28,902		—			3,970		—			32,872
Non-U.S. government & agency		10,298		—			667		—			10,965
Agency MBS		384,015		—			18,789		(733	)		402,071
ABS/CMBS/MBS*		213,223		(17	)		5,580		(413	)		218,373
Corporate		753,404		(380	)		64,501		(933	)		816,592
Municipal		501,515		—			31,099		(218	)		532,396
Total Fixed Income	$	2,061,467	$	(397	)	$	138,110	$	(2,554	)	$	2,196,626

* Non-agency asset-backed, commercial mortgage-backed and mortgage-backed securities

Schedule of Debt Securities Available-for-sale Allowance for Credit Loss

	Three Months Ended March 31,
(in thousands)	2021			2020
Beginning balance	$	397		$	—
Adoption impact of ASU 2016-13		-			28
Increase to allowance from securities for which credit losses were not previously recorded		-			624
Net increase (decrease) from securities that had an allowance at the beginning of the period		(22	)		226
Balance as of March 31,	$	375		$	878

Schedule of Securities in an Unrealized Loss Position Segregated by Type and Length of Time in an Unrealized Loss Position

	March 31, 2021									December 31, 2020
(in thousands)	< 12 Mos.			12 Mos. & Greater			Total			< 12 Mos.			12 Mos. & Greater			Total
U.S. government
Fair value	$	4,864		$	—		$	4,864		$	5,680		$	—		$	5,680
Amortized cost		5,937			—			5,937			5,937			—			5,937
Unrealized loss	$	(1,073	)	$	—		$	(1,073	)	$	(257	)	$	—		$	(257	)
Non-U.S. government
Fair value	$	2,852		$	—		$	2,852		$	—		$	—		$	—
Amortized cost		3,000			—			3,000			—			—			—
Unrealized Loss	$	(148	)	$	—		$	(148	)	$	—		$	—		$	—
Agency MBS
Fair value	$	92,446		$	—		$	92,446		$	43,999		$	—		$	43,999
Amortized cost		95,465			—			95,465			44,732			—			44,732
Unrealized loss	$	(3,019	)	$	—		$	(3,019	)	$	(733	)	$	—		$	(733	)
ABS/CMBS/MBS*
Fair value	$	55,703		$	7,235		$	62,938		$	32,771		$	16,161		$	48,932
Amortized cost		56,341			7,255			63,596			33,094			16,251			49,345
Unrealized loss	$	(638	)	$	(20	)	$	(658	)	$	(323	)	$	(90	)	$	(413	)
Corporate
Fair value	$	165,717		$	14,193		$	179,910		$	52,655		$	6,235		$	58,890
Amortized cost		170,204			14,370			184,574			53,440			6,383			59,823
Unrealized loss	$	(4,487	)	$	(177	)	$	(4,664	)	$	(785	)	$	(148	)	$	(933	)
Municipal
Fair value	$	115,596		$	—		$	115,596		$	25,676		$	—		$	25,676
Amortized cost		121,072			—			121,072			25,894			—			25,894
Unrealized loss	$	(5,476	)	$	—		$	(5,476	)	$	(218	)	$	—		$	(218	)
Total fixed income
Fair value	$	437,178		$	21,428		$	458,606		$	160,781		$	22,396		$	183,177
Amortized cost		452,019			21,625			473,644			163,097			22,634			185,731
Unrealized loss	$	(14,841	)	$	(197	)	$	(15,038	)	$	(2,316	)	$	(238	)	$	(2,554	)

* Non-agency asset-backed, commercial mortgage-backed and mortgage-backed securities

Schedule of Credit Quality Indicators for Investments in Unrealized Loss Positions

	Equivalent	Equivalent	(dollars in thousands)
NAIC	S&P	Moody’s	Amortized				Unrealized			Percent
Rating	Rating	Rating	Cost		Fair Value		Loss			to Total
1	AAA/AA/A	Aaa/Aa/A	$	365,229	$	352,591	$	(12,638	)		84.1	%
2	BBB	Baa		55,575		54,161		(1,414	)		9.4	%
3	BB	Ba		23,838		23,455		(383	)		2.5	%
4	B	B		26,201		25,616		(585	)		3.9	%
5	CCC	Caa		2,801		2,783		(18	)		0.1	%
6	CC or lower	Ca or lower		-		-		-			0.0	%
		Total	$	473,644	$	458,606	$	(15,038	)		100.0	%