Fair Value of Financial Measurements - Carrying Value (Details) - USD ($)	Mar. 31, 2022	Dec. 31, 2021
Liabilities:
Contingent consideration	$ 56,142,000	$ 80,477,000
Recurring
Other assets
Marketable securities - restricted (SERP)	570,000	630,000
Total assets at fair value	438,107,000	459,476,000
Liabilities:
Contingent consideration	56,142,000	80,477,000
Total liabilities at fair value	56,142,000	80,477,000
Recurring \| Corporate and municipal debt securities
Marketable securities
Corporate and municipal debt securities	196,485,000	136,246,000
Long-term marketable securities
Corporate and municipal debt securities	125,337,000	119,166,000
Recurring \| Cash
Cash and cash equivalents
Cash and Money market funds	84,218,000	148,863,000
Recurring \| Money market securities and funds
Cash and cash equivalents
Cash and Money market funds	31,497,000	54,571,000
Recurring \| Level 1
Other assets
Marketable securities - restricted (SERP)	8,000	7,000
Total assets at fair value	85,728,000	203,692,000
Liabilities:
Contingent consideration	0	0
Total liabilities at fair value	0	0
Recurring \| Level 1 \| Corporate and municipal debt securities
Marketable securities
Corporate and municipal debt securities	0	251,000
Long-term marketable securities
Corporate and municipal debt securities	0	0
Recurring \| Level 1 \| Cash
Cash and cash equivalents
Cash and Money market funds	84,218,000	148,863,000
Recurring \| Level 1 \| Money market securities and funds
Cash and cash equivalents
Cash and Money market funds	1,502,000	54,571,000
Recurring \| Level 2
Other assets
Marketable securities - restricted (SERP)	562,000	623,000
Total assets at fair value	352,379,000	255,784,000
Liabilities:
Contingent consideration	0	0
Total liabilities at fair value	0	0
Recurring \| Level 2 \| Corporate and municipal debt securities
Marketable securities
Corporate and municipal debt securities	196,485,000	135,995,000
Long-term marketable securities
Corporate and municipal debt securities	125,337,000	119,166,000
Recurring \| Level 2 \| Cash
Cash and cash equivalents
Cash and Money market funds	0	0
Recurring \| Level 2 \| Money market securities and funds
Cash and cash equivalents
Cash and Money market funds	29,995,000	0
Recurring \| Level 3
Other assets
Marketable securities - restricted (SERP)	0	0
Total assets at fair value	0	0
Liabilities:
Contingent consideration	56,142,000	80,477,000
Total liabilities at fair value	56,142,000	80,477,000
Recurring \| Level 3 \| Corporate and municipal debt securities
Marketable securities
Corporate and municipal debt securities	0	0
Long-term marketable securities
Corporate and municipal debt securities	0	0
Recurring \| Level 3 \| Cash
Cash and cash equivalents
Cash and Money market funds	0	0
Recurring \| Level 3 \| Money market securities and funds
Cash and cash equivalents
Cash and Money market funds	$ 0	$ 0

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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