Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2018

Fair Value Disclosures [Abstract]

Components of Long-Term Debt and Methods Used in Estimating Fair Values

The following table summarizes components of the Company’s long-term debt and methods used in estimating their fair values:

	Maturity Date	Valuation Methodology
3.875% Convertible Senior Notes	2019	Quoted price
4.25% Convertible Senior Notes	2037	Quoted price
3.95% Promissory Note	2020	Discounted cash flow method/Level 3 inputs
4% Promissory Note	2031	Discounted cash flow method/Level 3 inputs
3.75% Callable Promissory Note	2036	Discounted cash flow method/Level 3 inputs
4.55% Promissory Note	2036	Discounted cash flow method/Level 3 inputs

Assets Measured at Estimated Fair Value on a Recurring Basis

Assets Measured at Estimated Fair Value on a Recurring Basis:

The following tables present information about the Company’s financial assets measured at estimated fair value on a recurring basis. The table indicates the fair value hierarchy of the valuation techniques utilized by the Company to determine such fair value as of December 31, 2018 and 2017:

	Fair Value Measurements Using
	(Level 1)		(Level 2)		(Level 3)		Total
As of December 31, 2018
Financial Assets:
Cash and cash equivalents	$	239,458	$	—	$	—	$	239,458
Restricted cash		700		—		—		700
Short-term investments		66,479		—		—		66,479
Fixed-maturity securities:
U.S. Treasury and U.S. government agencies		60,297		1,500		—		61,797
Corporate bonds		101,905		—		—		101,905
State, municipalities, and political subdivisions		—		10,662		—		10,662
Exchange-traded debt		8,247		—		—		8,247
Redeemable preferred stock		112		—		—		112
Total available-for-sale securities		170,561		12,162		—		182,723
Equity securities		41,143		—		—		41,143
Total	$	518,341	$	12,162	$	—	$	530,503

	Fair Value Measurements Using
	(Level 1)		(Level 2)		(Level 3)		Total
As of December 31, 2017
Financial Assets:
Cash and cash equivalents	$	255,884	$	—	$	—	$	255,884
Restricted cash		809		—		—		809
Fixed-maturity securities:
U.S. Treasury and U.S. government agencies		40,527		1,500		—		42,027
Corporate bonds		106,109		994		—		107,103
State, municipalities, and political subdivisions		—		80,695		—		80,695
Exchange-traded debt		7,659		—		—		7,659
Total available-for-sale securities		154,295		83,189		—		237,484
Equity securities		59,956		—		—		59,956
Total	$	470,944	$	83,189	$	—	$	554,133

Schedule of Fair Value Information for Financial Assets and Liabilities Carried on Balance Sheet

The following tables present fair value information for assets and liabilities that are carried on the balance sheet at amounts other than fair value as of December 31, 2018 and 2017:

	Carrying		Fair Value Measurements Using						Estimated
	Value		(Level 1)		(Level 2)		(Level 3)		Fair Value
As of December 31, 2018
Financial Assets:
Limited partnership investments	$	32,293	$	—	$	—	$	32,293	$	32,293
Financial Liabilities:
Long-term debt:
3.875% Convertible senior notes	$	89,181	$	—	$	89,824	$	—	$	89,824
4.25% Convertible senior notes		130,120		—		145,617		—		145,617
3.95% Promissory note		9,077		—		—		9,128		9,128
4% Promissory note		7,732		—		—		7,788		7,788
3.75% Promissory note		8,159		—		—		8,001		8,001
4.55% Promissory note		5,826		—		—		6,025		6,025
Total long-term debt	$	250,095	$	—	$	235,441	$	30,942	$	266,383

	Carrying		Fair Value Measurements Using						Estimated
	Value		(Level 1)		(Level 2)		(Level 3)		Fair Value
As of December 31, 2017
Financial Assets:
Limited partnership investments	$	23,184	$	—	$	—	$	23,184	$	23,184
Financial Liabilities:
Long-term debt:
3.875% Convertible senior notes	$	85,436	$	—	$	90,827	$	—	$	90,827
4.25% Convertible senior notes		126,454		—		124,444		—		124,444
3.95% Promissory note		9,270		—		—		9,227		9,227
4% Promissory note		8,206		—		—		7,894		7,894
3.75% Promissory note		8,469		—		—		7,820		7,820
Total long-term debt	$	237,835	$	—	$	215,271	$	24,941	$	240,212