Note 12 - Other Income (Expense), Net - Interest and Other Income Components (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Interest income	$ 5,965	$ 3,333	$ 10,773	$ 6,794
Amortization of discount (premium) on available-for-sale securities	204	(1,232)	(56)	(2,580)
Gain (loss) on deferred compensation plan investments	2,488	(5,085)	5,022	(7,277)
Charitable contributions	(3,800)	(2,500)	(5,800)	(3,000)
Gain on sales of equity investments	1,424	0	1,424	(0)
Other	262	392	477	337
Total	$ 6,543	$ (5,092)	$ 11,840	$ (5,726)