Financial Instruments and Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2019

Financial Instruments and Fair Value Measurements

Schedule of Financial Instruments Measured at Fair Value on Recurring Basis

The financial instruments measured at fair value on a recurring basis are as follows:

	December 31, 2019
							Total Fair
	Level 1		Level 2		Level 3		Value
Cash equivalents:
Money market funds	$	21,043	$	—	$	—	$	21,043
Commercial paper		138,220		—		—		138,220
U.S. Treasury Bills		6,990		—		—		6,990
		166,253		—		—		166,253
Investments - debt securities:
Corporate debt securities		—		53		—		53
		—		53		—		53
Investments - equity securities:
Preferred stock		—		9,746		—		9,746
		—		9,746		—		9,746
Restricted investments:
Short-term bond		2,250		—		—		2,250
Money market fund		114		—		—		114
		2,364		—		—		2,364
	$	168,617	$	9,799	$	—	$	178,416

	December 31, 2018
							Total Fair
	Level 1		Level 2		Level 3		Value
Cash equivalents:
Money market funds	$	43,346	$	—	$	—	$	43,346
Commercial paper		107,586		—		—		107,586
U.S. Treasury Bills		29,998		—		—		29,998
		180,930		—		—		180,930
Investments - debt securities:
U.S. Treasury Bills		6,937		—		—		6,937
Corporate debt securities		—		2,021		—		2,021
		6,937		2,021		—		8,958
Investments - equity securities:
Preferred stock		10,470		25,662		—		36,132
Restricted investments:
Short-term bond		3,265		—		—		3,265
Money market fund		167		—		—		167
		3,432		—		—		3,432
	$	201,769	$	27,683	$	—	$	229,452

Schedule of Liabilities Measured at Fair Value on Recurring Basis

		December 31, 2019
	Location in							Total Fair
	Balance Sheet	Level 1		Level 2		Level 3		Value
Derivative Liabilities:
Interest rate swap	Other liabilities	$	—	$	336	$	—	$	336
		$	—	$	336	$	—	$	336

Schedule of Carrying Amount and Fair Value Measured on Nonrecurring Basis of Financial Instruments

	December 31, 2019					December 31, 2018
	Carrying		Estimated			Carrying		Estimated
	value		Fair value		Level	value		Fair value		Level
Assets
Investments held by SPEs:
Time deposit	$	200,000	$	200,000	3	$	200,000	$	200,000	3
U.S. Treasury Bills and cash	$	6,771	$	6,712	1	$	7,384	$	7,092	1
Liabilities
Debt
Fixed-rate debt	$	89,969	$	92,276	2	$	68,146	$	67,126	2
Variable-rate debt		4,538		4,538	2		2,830		2,830	2
Total debt	$	94,507	$	96,814		$	70,976	$	69,956
Senior Notes held by SPE	$	177,026	$	204,347	3	$	176,775	$	193,293	3