Note 6 - Income Taxes - Income Before Income Taxes. (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Income before income taxes	$ 794,112	$ 759,516	$ 934,887
Domestic Tax Jurisdiction [Member]
Income before income taxes	772,284	742,432	929,054
Foreign Tax Jurisdiction [Member]
Income before income taxes	$ 21,828	$ 17,084	$ 5,833