Note 8 - Income Taxes - Components of Income Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
United States	$ 37,248	$ 31,246	$ 45,166
Current expense:
Federal	5,174	4,058	8,204
Foreign	1,087	353	1,140
State and local	1,086	1,103	1,205
Total current	7,347	5,514	10,549
Deferred expense (benefit):
Federal	60	728	(720)
Foreign	48	(349)	(379)
State and local	(58)	165	(99)
Total deferred	50	544	(1,198)
Income tax expense	7,397	6,058	9,351
UNITED STATES
United States	30,973	28,493	41,234
Foreign Countries [Member]
United States	$ 6,275	$ 2,753	$ 3,932