Note 13 - Long-term Debt and Credit Arrangements - Schedule of Long-term Debt (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020
Total debt	$ 339,931	$ 338,800	$ 414,023
Debt issuance costs and other	8,660	7,247	7,077
Long-term Debt, Current Maturities, Total	8,709	8,278	8,253
Long-term Debt, Excluding Current Maturities, Total	331,222	330,522	405,770
Convertible Debt [Member] | The 2.75% Convertible Notes [Member]
Total debt	203,771	200,303	196,946
Term Loan [Member] | The Credit Agreement [Member]
Total debt	127,500	131,250	135,000
Long-term Debt, Current Maturities, Total	7,500	7,500	7,500
Long-term Debt, Excluding Current Maturities, Total	120,000	123,800	127,500
Line of Credit [Member] | The Credit Agreement [Member] | Revolving Credit Facility [Member]
Total debt	$ 0	$ 0	$ 75,000