Note 10 - Fair Value Measurement (Details Textual) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021	Oct. 31, 2021	May 31, 2018
Derivative Liability, Notional Amount							$ 150,000
Interest Expense, Total	$ 3,896	$ 5,502	$ 7,471	$ 10,874
The 2.75% Convertible Notes [Member]
Debt Instrument, Interest Rate, Stated Percentage	2.75%		2.75%
Debt Instrument, Convertible, Carrying Amount of Equity Component		$ 26,200		$ 26,200	$ 22,600
Interest Rate Swap [Member]
Interest Expense, Total	$ 1,500		$ 2,200
Commodity Contract [Member]
Derivative, Notional Amount	15,000		15,000			$ 4,900
Gain (Loss) on Sale of Commodity Contracts	2,400		2,800
Unrealized Gain (Loss) on Derivatives and Commodity Contracts, Total	$ (500)		2,800
Derivative, Gain (Loss) on Derivative, Net, Total			$ 1,000