Note 3 - Financing Arrangements - Outstanding Borrowings (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Sep. 30, 2022	Dec. 31, 2021
Long-term debt	$ 1,261,738		$ 945,257
Less current portion of long-term debt	$ 0	$ 0	(355,972)
Total long-term debt		1,261,700	945,200
Senior Notes [Member]
Long-term debt		947,000	1,301,200
Revolving Credit Facility [Member]
Long-term debt		$ 314,700	$ 0