Note 10 - Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Contingency [Line Items]
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	$ 3,100
Unrecognized Tax Benefits, Interest and Penalties Charged to Income	300	$ 1,300	$ 61,600
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of period	37,208	33,552
Tax positions related to the current year [Abstract]
Unrecognized Tax Benefits, Increases Resulting from Current Period Tax Positions	250	3,215
Unrecognized Tax Benefits, Decrease Resulting from Current Period Tax Positions	(1,788)	0
Tax positions related to prior years [Abstract]
Unrecognized Tax Benefits, Increases Resulting from Prior Period Tax Positions	16,568	441
Unrecognized Tax Benefits, Decreases Resulting from Prior Period Tax Positions	(171)	0
Unrecognized Tax Benefits, Reductions Resulting from Lapse of Applicable Statute of Limitations	(31,818)	0
Balance at end of period	20,249	$ 37,208	$ 33,552
Unrecognized Tax Benefits, Period Increase (Decrease)	(17,000)
Interest and Penalties [Member]
Income Tax Contingency [Line Items]
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	$ 1,600