Note 12 - Commitments and Contingencies (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Oct. 31, 2001
Future Annual Payment To Chairman and Chief Executive Officer			$ 650
Deferred Compensation Arrangement with Individual Gain (Loss)			$ 1,700
Deferred Compensation Liability, Current and Noncurrent, Total	$ 1,800
Deferred Compensation Liability, Current, Total	$ 1,500
Minimum [Member]
Long-term Incentive Plan, Bonus Pool Percent	0.20%	1.00%
Maximum [Member]
Long-term Incentive Plan, Bonus Pool Percent	1.30%
Employee Severance [Member]
Restructuring and Related Cost, Expected Cost, Total	$ 2,300
Private Equity Funds [Member]
Guarantor Obligations, Current Carrying Value	$ 3,800