Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 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:

	December 31, 2021
	Total		Level 1		Level 2		Level 3
	(in thousands)
Equity securities, debt securities and cash equivalents:
Corporate debt securities	$	332,529	$	—	$	332,529	$	—
U.S. government debt securities		198,157		—		198,157		—
Bond funds		98,799		98,799		—		—
U.S. agency debt securities		69,534		—		69,534		—
Exchange traded funds		35,000		35,000		—		—
Municipal bonds		24,480		—		24,480		—
Yankee debt securities		12,153		—		12,153		—
Redeemable preferred stock investment		21,965		—		—		21,965
Money market accounts		77,067		77,067		—		—
Total equity securities, debt securities and cash equivalents	$	869,684	$	210,866	$	636,853	$	21,965

	December 31, 2020
	Total		Level 1		Level 2		Level 3
	(in thousands)
Equity securities, debt securities and cash equivalents:
Corporate debt securities	$	166,599	$	—	$	166,599	$	—
Bond funds		153,185		153,185		—		—
Exchange traded funds		17,609		17,609		—		—
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	$	—