Note 13 - Long-term Debt and Credit Arrangements - Schedule of Long-term Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020
Total debt	$ 340,347	$ 338,800	$ 364,164
Debt issuance costs and other	8,954	7,247	6,994
Long-term Debt, Current Maturities, Total	8,700	8,278	8,253
Long-term Debt, Excluding Current Maturities, Total	331,647	330,522	355,911
Convertible Debt [Member] | The 2.75% Convertible Notes [Member]
Total debt	202,018	200,303	195,295
Term Loan [Member] | The Credit Agreement [Member]
Total debt	129,375	131,250	136,875
Long-term Debt, Current Maturities, Total	7,500	7,500	7,500
Long-term Debt, Excluding Current Maturities, Total	121,900	123,800	129,400
Line of Credit [Member] | The Credit Agreement [Member] | Revolving Credit Facility [Member]
Total debt	$ 0	$ 0	$ 25,000