Note 5 - Stockholders' Equity and Dilutive Equity Instruments - Changes in Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Balance	$ 1,111,185	$ 1,037,697
Unrealized gain on note receivable	0	80
Balance	1,110,365	1,055,153
AOCI Attributable to Parent [Member]
Balance	6,060	5,266
Unrealized gain on note receivable	0	80
Balance	6,607	5,209
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Before reclassifications	$ 547	$ (137)