Note 4 - Financing Arrangements - Outstanding Borrowings (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Senior notes	$ 945,628	$ 945,257
Less current portion of long-term debt	(351,214)	(355,972)
Senior Notes [Member]
Senior notes	1,296,800	1,301,200
Less current portion of long-term debt	(351,200)	(356,000)
Long-Term Debt, Total	$ 945,600	$ 945,200