Investments (Tables)

12 Months Ended

Dec. 31, 2018

Investments

Schedule of Investments

Investments classified as available-for-sale securities were as follows:

	December 31, 2018
			Gross Unrealized		Gross Unrealized
	Amortized Cost		Gains		(Losses)		Fair Value
Investments - debt securities:
U.S. Treasury securities	$	6,936	$	1	$	—	$	6,937
Corporate debt securities		2,908		—		(887)		2,021
		9,844		1		(887)		8,958
Restricted investments:
Short-term bond		3,274		—		(9)		3,265
Money market fund		167		—		—		167
		3,441		—		(9)		3,432
	$	13,285	$	1	$	(896)	$	12,390

	December 31, 2017
			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 available-for-sale investments unrealized loss position and related fair values:

	December 31, 2018
	Less Than 12 Months				12 Months or Greater
			Unrealized				Unrealized
	Fair Value		Losses		Fair Value		Losses
Investments - debt securities:
Corporate debt securities	$	—	$	—	$	1,843	$	887
Restricted investments:
Short-term bond		—		—		3,265		9
	$	—	$	—	$	5,108	$	896

	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

	December 31, 2018
	Amortized Cost		Fair Value
Due in one year or less	$	9,844	$	8,958
Restricted investments		3,441		3,432
	$	13,285	$	12,390