Note 10 - Income Taxes - Income Tax Provision (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Current provision (benefit)	$ (16,264)	$ 19,522	$ (42,398)
Deferred provision (benefit)	102,079	157,162	120,573
Total income tax provision (benefit)	$ 85,815	$ 176,684	$ 78,175