Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2021

Fair Value Disclosures [Abstract]

Information about Financial Assets Measured at Fair Value on Recurring Basis Based on Three-Tier Fair Value Hierarchy

The following tables present information about the Company’s financial assets measured at fair value on a recurring basis, based on the three-tier fair value hierarchy:

	September 30, 2021
	Total		Level 1		Level 2		Level 3
	(in thousands)
Equity securities, debt securities and cash equivalents:
Bond funds	$	128,987	$	128,987	$	—	$	—
Exchange traded funds		35,090		35,090		—		—
Corporate debt securities		357,762		—		357,762		—
U.S. government debt securities		64,135		—		64,135		—
U.S. agency debt securities		39,693		—		39,693		—
Municipal bonds		24,389		—		24,389		—
Yankee debt securities		12,330		—		12,330		—
Redeemable preferred stock investment		20,000		—		—		20,000
Money market accounts		50,425		50,425		—		—
Total equity securities, debt securities and cash equivalents	$	732,811	$	214,502	$	498,309	$	20,000

	December 31, 2020
	Total		Level 1		Level 2		Level 3
	(in thousands)
Equity securities, debt securities and cash equivalents:
Bond funds	$	153,185	$	153,185	$	—	$	—
Exchange traded funds		17,609		17,609		—		—
Corporate debt securities		166,599		—		166,599		—
Yankee debt securities		6,048		—		6,048		—
U.S. agency debt securities		1,002		—		1,002		—
Money market accounts		47,461		47,461		—		—
Total equity securities, debt securities and cash equivalents	$	391,904	$	218,255	$	173,649	$	—