Note 6 - Goodwill and Intangible Assets (Details Textual)		12 Months Ended
	Nov. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Business Acquisition Number of Acquisitions Resulting in Goodwill		5
Equity, Fair Value Disclosure, Total	$ 89,000,000
Stockholders' Equity Attributable to Parent, Ending Balance	87,400,000	$ 91,480,000	$ 85,858,000	$ 79,827,000
Goodwill, Impairment Loss	$ 0	$ 0	0
Business Acquisition, Number of Acquisitions Resulting in Intangible Assets		3
Amortization of Intangible Assets, Total		$ 164,000	$ 176,000