CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
Net income	$ 55,735	$ 170,851	$ 164,413
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments, net of $0 tax in 2023, 2022 and 2021	(420)	(985)	(486)
Unrealized gain (loss) on marketable securities, net of $0 tax in 2023, 2022 and 2021	5,579	(4,158)	(2,055)
Unrealized actuarial gain on pension benefits, net of tax of ($130), ($271) and ($334) in 2023, 2022 and 2021, respectively	723	1,536	967
Total other comprehensive income (loss)	5,882	(3,607)	(1,574)
TOTAL COMPREHENSIVE INCOME	$ 61,617	$ 167,244	$ 162,839