Note 10 - Stockholders' Equity - Changes in Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Balance at December 31	$ 1,111,185	$ 1,037,697	$ 865,990
Unrealized gain on note receivable	0	283	213
Balance at December 31	1,361,254	1,111,185	1,037,697
AOCI Attributable to Parent [Member]
Balance at December 31	6,060	5,266	8,576
Unrealized gain on note receivable	0	283	213
Balance at December 31	7,248	6,060	5,266
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Before reclassifications	$ 1,188	$ 511	$ (3,523)