Note 8 - Income Tax - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax liabilities:
Amortization	$ (10,913)	$ (11,133)
Depreciation	(11,716)	(10,934)
Lease asset	(406)	(306)
Prepaid expense	(306)	(506)
Other	(7)	(8)
Total deferred tax liabilities	(23,348)	(22,887)
Deferred tax assets:
Deferred compensation	113	147
Advance payments	542	597
Lease liability	406	306
Bad debt	67	77
Consulting	499
Other	207	239
Total deferred tax assets	$ 1,834	$ 1,366