CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited)
Net income	$ 19,796	$ 45,964	$ 41,464	$ 148,036
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments, net of $0 tax in each of the three and nine months ended September 30, 2023 and 2022	(407)	(1,044)	(807)	(2,067)
Unrealized gain (loss) on marketable securities, net of $0 tax in each of the three and nine months ended September 30, 2023 and 2022	455	(731)	2,483	(6,072)
Amortization of defined benefit pension items, net of tax of ($4) and ($11) in the three and nine months ended September 30, 2023, respectively, and $3 and $6 in the three and nine months ended September 30, 2022, respectively	(21)	18	(62)	59
Total other comprehensive income (loss)	27	(1,757)	1,614	(8,080)
TOTAL COMPREHENSIVE INCOME	$ 19,823	$ 44,207	$ 43,078	$ 139,956