Note 7 - Income Tax Expense (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	21.00%	34.00%
Income Tax Expense (Benefit), Total	$ 3,220	$ 4,420	$ 9,760
Tax Adjustments, Settlements, and Unusual Provisions			4,000
Net Discrete Tax Adjustment, Tax Act			3,300
Net Discrete Tax Adjustment, Other Miscellaneous Discrete Items			700
Accumulated Foreign Earnings and Profits Tax Rate, Liquid Assets		15.50%
Accumulated Foreign Earnings and Profits Tax Rate, Unremitted Foreign E&P		8.00%
Additional Deferred Tax Expense	900
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense, Total	200	$ 100	100
Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations	100	100	$ 100
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued, Total	200	100
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit	$ 100
Domestic Tax Authority [Member]
Open Tax Year	2016 2017 2018 2019
State and Local Jurisdiction [Member]
Open Tax Year	2013 2014 2015 2016 2017 2018 2019
Other Noncurrent Liabilities [Member]
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	$ 900	$ 600