CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 170,851	$ 164,413	$ 71,176
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments, net of $0 tax in 2022, 2021 and 2020	(985)	(486)	(183)
Unrealized gain (loss) on marketable securities, net of $0 tax in 2022, 2021 and 2020	(4,158)	(2,055)	307
Unrealized actuarial gain on pension benefits, net of tax of ($271), ($334) and ($308) in 2022, 2021 and 2020, respectively	1,536	967	843
Total other comprehensive income (loss)	(3,607)	(1,574)	967
TOTAL COMPREHENSIVE INCOME	$ 167,244	$ 162,839	$ 72,143