Note 13 - Income Taxes (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Effective Income Tax Rate Reconciliation, Share-based Compensation, Excess Tax Expense (Benefit), Amount	$ (263,000)	$ (136,000)	$ (237,000)
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability			(8,488,000)
Unrecognized Tax Benefits, Period Increase (Decrease), Total	(1,604,000)
Effective Income Tax Rate Reconciliation, Benefit Resulting from Expiration of Applicable Statute Limitations, Amount	2,064,000	2,222,000	1,753,000
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit	2,834,000
Income Tax Examination, Penalties and Interest Expense, Total	38,000	(4,000)	(62,000)
Liability for Interest and Penalties [Member]
Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations	935,000	941,000	927,000
Unrecognized Tax Benefits, Ending Balance	3,309,000	$ 3,271,000	$ 3,275,000	$ 3,337,000
Permanent Differences [Member]
Unrecognized Tax Benefits, Ending Balance	$ 5,829,000