Investments (Tables)

12 Months Ended

Dec. 31, 2019

Investments [Abstract]

Amortized Cost and Estimated Fair Value of Investments in Debt and Equity Securities by Category

The cost or amortized cost and the estimated fair value of investments in debt and equity securities by category is as follows (in thousands):

			Gross		Gross
		Cost/Amortized	Unrealized		Unrealized
	Cost		Gains		Losses		Fair Value
As of December 31, 2019
U.S. Treasury securities and obligations of U.S. Government	$	66,441	$	162	$	(3)	$	66,600
Corporate bonds		297,601		3,387		(163)		300,825
Collateralized corporate bank loans		115,669		556		(468)		115,757
Municipal bonds		81,787		1,531		(48)		83,270
Mortgage-backed		8,000		46		(219)		7,827
Total debt securities		569,498		5,682		(901)		574,279
Total equity securities		71,895		35,028		(7,708)		99,215
Total other investments		3,763		—		(1,594)		2,169
Total investments	$	645,156	$	40,710	$	(10,203)	$	675,663
As of December 31, 2018
U.S. Treasury securities and obligations of U.S. Government	$	48,609	$	5	$	(508)	$	48,106
Corporate bonds		243,314		440		(1,602)		242,152
Collateralized corporate bank loans		131,779		19		(5,270)		126,528
Municipal bonds		112,574		3,791		(838)		115,527
Mortgage-backed		13,992		11		(446)		13,557
Total debt securities		550,268		4,266		(8,664)		545,870
Total equity securities		68,709		20,693		(8,506)		80,896
Total other investments		3,763		—		(2,615)		1,148
Total investments	$	622,740	$	24,959	$	(19,785)	$	627,914

Major Categories of Investment Income

Major categories of net investment income are summarized as follows (in thousands):

	Twelve Months Ended December 31,
	2019		2018
U.S. Treasury securities and obligations of U.S. Government	$	916	$	902
Corporate bonds		7,317		6,696
Collateralized corporate bank loans		6,028		5,658
Municipal bonds		3,907		3,757
Mortgage-backed		311		521
Equity securities		2,364		1,151
Cash and cash equivalents		766		518
		21,609		19,203
Investment expenses		(1,005)		(971)
Investment income, net of expenses	$	20,604	$	18,232

Major Categories of Net Investment Gains (Losses) on Investments

Major categories of net investment gains (losses) on investments are summarized as follows (in thousands):

	Year Ended December 31,
	2019		2018
U.S. Treasury securities and obligations of U.S. Government	$	—	$	—
Corporate bonds		235		(83)
Collateralized corporate bank loans		(34)		90
Municipal bonds		4,270		1,435
Mortgage-backed		—		2
Equity securities		(7)		359
Gain on investments		4,464		1,803
Unrealized gains (losses) on equity securities		15,133		(9,322)
Unrealized gains (losses) on other investments		1,021		(2,676)
Investment gains (losses), net	$	20,618	$	(10,195)

Summary of Gross Unrealized Loss Position

The following schedules summarize the gross unrealized losses showing the length of time that investments have been continuously in an unrealized loss position as of December 31, 2019 and December 31, 2018 (in thousands):

	As of December 31, 2019
	12 months or less				Longer than 12 months				Total
			Unrealized				Unrealized				Unrealized
	Fair Value		Losses		Fair Value		Losses		Fair Value		Losses
U.S. Treasury securities and obligations of U.S. Government	$	—	$	—	$	5,513	$	(3)	$	5,513	$	(3)
Corporate bonds		27,268		(144)		1,150		(19)		28,418		(163)
Collateralized corporate bank loans		9,000		(41)		10,228		(427)		19,228		(468)
Municipal bonds		4,808		(29)		1,618		(19)		6,426		(48)
Mortgage-backed		1,712		(101)		562		(118)		2,274		(219)
Total debt securities		42,788		(315)		19,071		(586)		61,859		(901)
Total equity securities		10,905		(2,363)		6,093		(5,345)		16,998		(7,708)
Total other investments		—		—		2,169		(1,594)		2,169		(1,594)
Total investments	$	53,693	$	(2,678)	$	27,333	$	(7,525)	$	81,026	$	(10,203)

	As of December 31, 2018
	12 months or less				Longer than 12 months				Total
			Unrealized				Unrealized				Unrealized
	Fair Value		Losses		Fair Value		Losses		Fair Value		Losses
U.S. Treasury securities and obligations of U.S. Government	$	18,902	$	(181)	$	28,201	$	(327)	$	47,103	$	(508)
Corporate bonds		117,450		(907)		100,060		(695)		217,510		(1,602)
Collateralized corporate bank loans		120,410		(4,938)		4,931		(332)		125,341		(5,270)
Municipal bonds		14,281		(96)		25,891		(742)		40,172		(838)
Mortgage-backed		6,592		(60)		5,986		(386)		12,578		(446)
Total debt securities		277,635		(6,182)		165,069		(2,482)		442,704		(8,664)
Total equity securities		30,981		(3,699)		4,475		(4,807)		35,456		(8,506)
Total other investments		1,148		(2,615)		—		—		1,148		(2,615)
Total investments	$	309,764	$	(12,496)	$	169,544	$	(7,289)	$	479,308	$	(19,785)

Carrying Value of Other Invested Assets Portfolio

	December 31,		December 31,
	2019		2018
Investment Type
Equity warrant	$	2,169	$	1,148
Total other investments	$	2,169	$	1,148

Schedule of Amortized Cost and Estimated Fair Value of Debt Securities by Contractual Maturities

	Amortized Cost		Fair Value
	(in thousands)
Due in one year or less	$	107,108	$	107,605
Due after one year through five years		342,962		345,860
Due after five years through ten years		87,669		88,061
Due after ten years		23,760		24,926
Mortgage-backed		7,999		7,827
	$	569,498	$	574,279