Investments (Tables)

6 Months Ended

Jun. 30, 2018

Investments

Schedule of Investments

At June 30, 2018, investments - debt securities and restricted investments classified as available-for-sale securities were as follows:

			Gross Unrealized		Gross Unrealized
	Amortized Cost		Gains		Losses		Fair Value
Investments - debt securities:
U.S. Treasury securities	$	9,961	$	—	$	15	$	9,946
Corporate debt securities		5,042		28		814		4,256
		15,003		28		829		14,202
Restricted investments:
Short-term bond		3,252		—		13		3,239
Money market fund		167		—		—		167
		3,419		—		13		3,406
	$	18,422	$	28	$	842	$	17,608

At December 31, 2017, investments - debt securities, investments - equity securities and restricted investments classified as available-for-sale securities were as follows:

			Gross Unrealized		Gross Unrealized
	Amortized Cost		Gains		Losses		Fair Value
Investments - debt securities:
U.S. Treasury securities	$	9,892	$	—	$	22	$	9,870
Corporate debt securities		67,781		411		1,817		66,375
		77,673		411		1,839		76,245
Investments - equity securities:
Preferred stock		35,955		423		1,355		35,023
Restricted investments:
Short-term bond		4,264		—		13		4,251
Money market fund		218		—		—		218
		4,482		—		13		4,469
	$	118,110	$	834	$	3,207	$	115,737

Schedule of Unrealized Loss Position and Related Fair Value of Investments

The following table provides the U.S. Treasury securities, corporate debt securities and restricted investments unrealized loss position and related fair values as of June 30, 2018:

	Less Than 12 Months				12 Months or Greater
			Unrealized				Unrealized
	Fair Value		Losses		Fair Value		Losses
Investments - debt securities:
U.S. Treasury securities	$	9,946	$	15	$	—	$	—
Corporate debt securities		—		—		4,159		814
Restricted investments:
Short-term bond		—		—		3,239		13
	$	9,946	$	15	$	7,398	$	827

The following table provides the U.S. Treasury securities, corporate debt securities, preferred stock and restricted investments unrealized loss position and related fair values as of December 31, 2017:

	Less Than 12 Months				12 Months or Greater
			Unrealized				Unrealized
	Fair Value		Losses		Fair Value		Losses
Investments - debt securities:
U.S. Treasury securities	$	9,870	$	22	$	—	$	—
Corporate debt securities		15,515		691		29,595		1,126
Investments - equity securities:
Preferred stock		11,263		1,337		1,986		18
Restricted investments:
Short-term bond		—		—		4,251		13
	$	36,648	$	2,050	$	35,832	$	1,157

Schedule of Contractual Maturities of Investments

	Amortized Cost		Fair Value
Due in one year or less	$	12,654	$	12,393
Due after one year through five years		2,280		1,711
Due after five years through ten years		69		98
		15,003		14,202
Restricted investments		3,419		3,406
	$	18,422	$	17,608