Note 19 - Selected Quarterly Financial Data - Unaudited (Details Textual) - USD ($) $ in Thousands	3 Months Ended					12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Gain (Loss) on Derivative Instruments, Net, Pretax, Total	$ (18,700)	$ 5,900	$ 1,800	$ (48,900)	$ 59,700	$ (59,887)	$ 53,798	$ 4,199
Income Tax Expense (Benefit), Total	$ (8,200)	$ (55,500)	$ (11,700)	$ 200		(75,194)	535	(12,569)
Gain (Loss) on Extinguishment of Debt, Total					$ 47,100		$ 47,109	$ 7,811