Investments (Tables)

12 Months Ended

Dec. 31, 2017

Investments [Abstract]

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

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

As of December 31, 2017	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
U.S. Treasury securities and obligations of U.S. Government	$	50,088	$	7	$	(148)	$	49,947
Corporate bonds		278,611		1,204		(742)		279,073
Collateralized corporate bank loans		125,536		702		(301)		125,937
Municipal bonds		134,052		709		(505)		134,256
Mortgage-backed		16,712		37		(216)		16,533
Total debt securities		604,999		2,659		(1,912)		605,746
Total equity securities		30,253		23,014		(1,504)		51,763
Total other investments		3,763		61		-		3,824
Total investments	$	639,015	$	25,734	$	(3,416)	$	661,333
As of December 31, 2016
U.S. Treasury securities and obligations of U.S. Government	$	41,976	$	66	$	(20)	$	42,022
Corporate bonds		224,915		1,722		(575)		226,062
Collateralized corporate bank loans		105,220		959		(170)		106,009
Municipal bonds		165,900		956		(2,961)		163,895
Mortgage-backed		59,773		49		(353)		59,469
Total debt securities		597,784		3,752		(4,079)		597,457
Total equity securities		31,449		21,052		(790)		51,711
Total other investments		3,763		1,188		-		4,951
Total investments	$	632,996	$	25,992	$	(4,869)	$	654,119

Major Categories of Investment Income

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

	Twelve Months Ended December 31
	2017		2016		2015
U.S. Treasury securities and obligations of U.S. Government	$	566	$	594	$	670
Corporate bonds		7,839		5,573		1,435
Collateralized corporate bank loans		4,302		3,190		4,727
Municipal bonds		4,633		5,442		5,901
Mortgage-backed		1,049		1,320		1,288
Equity securities		871		638		673
Other investments		-		-		-
Cash and cash equivalents		706		277		148
		19,966		17,034		14,842
Investment expenses		(1,092)		(692)		(873)
Investment income, net of expenses	$	18,874	$	16,342	$	13,969

Major Categories of Net Realized Gains on Investments

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

	Twelve Months Ended December 31
	2017		2016		2015
U.S. Treasury securities and obligations of U.S. Government	$	-	$	-	$	-
Corporate bonds		(468)		(264)		-
Collateralized corporate bank loans		79		(86)		126
Municipal bonds		195		(189)		(83)
Mortgage-backed		(9)		(1)		240
Equity securities		7,002		1,871		5,543
Gain on investments		6,799		1,331		5,826
Unrealized (loss) gain on other investments		(1,127)		1,188		-
Other-than-temporary impairments		(5,877)		(2,888)		(3,323)
Net realized (losses) gains	$	(205)	$	(369)	$	2,503

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, 2017 and December 31, 2016 (in thousands):

	As of December 31, 2017
	12 months or less				Longer than 12 months				Total
	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
U.S. Treasury securities and obligations of U.S. Government	$	28,825	$	(145)	$	1,997	$	(3)	$	30,822	$	(148)
Corporate bonds		176,061		(736)		2,378		(6)		178,439		(742)
Collateralized corporate bank loans		30,008		(280)		2,517		(21)		32,525		(301)
Municipal bonds		35,200		(370)		8,917		(135)		44,117		(505)
Mortgage-backed		6,419		(127)		1,415		(89)		7,834		(216)
Total debt securities		276,513		(1,658)		17,224		(254)		293,737		(1,912)
Total equity securities		8,375		(1,504)		-		-		8,375		(1,504)
Total other investments		-		-		-		-		-		-
Total investments	$	284,888	$	(3,162)	$	17,224	$	(254)	$	302,112	$	(3,416)

	As of December 31, 2016
	12 months or less				Longer than 12 months				Total
	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
U.S. Treasury securities and obligations of U.S. Government	$	7,037	$	(20)	$	-	$	-	$	7,037	$	(20)
Corporate bonds		86,592		(575)		-		-		86,592		(575)
Collateralized corporate bank loans		2,637		(7)		8,314		(163)		10,951		(170)
Municipal bonds		70,633		(1,327)		13,574		(1,634)		84,207		(2,961)
Mortgage-backed		29,475		(348)		2,430		(5)		31,905		(353)
Total debt securities		196,374		(2,277)		24,318		(1,802)		220,692		(4,079)
Total equity securities		4,109		(483)		2,037		(307)		6,146		(790)
Total other investments		-		-		-		-		-		-
Total investments	$	200,483	$	(2,760)	$	26,355	$	(2,109)	$	226,838	$	(4,869)

Carrying Value of Other Invested Assets Portfolio

Details regarding the carrying value of the other invested assets portfolio as of December 31, 2017 and 2016 were as follows:

	2017		2016
Investment Type
Equity warrant	$	3,824	$	4,951
Total other investments	$	3,824	$	4,951

Schedule of Amortized Cost and Estimated Fair Value of Debt Securities

The amortized cost and estimated fair value of debt securities at December 31, 2017 by contractual maturity are as follows. Expected maturities may differ from contractual maturities because certain borrowers may have the right to call or prepay obligations with or without penalties.

	Amortized Cost			Fair Value
	(in thousands)
Due in one year or less	$	116,027	$	116,060
Due after one year through five years		308,477		308,829
Due after five years through ten years		123,518		124,168
Due after ten years		40,265		40,156
Mortgage-backed		16,712		16,533
	$	604,999	$	605,746