Note 2 - Acquisitions - Proforma Results (Details) - The 2021 Acquisitions [Member] - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenue, net	$ 146,966	$ 129,782	$ 399,372	$ 362,918
Net earnings	$ 5,734	$ 7,814	$ 17,043	$ 9,538
Common Class A [Member]
Earnings per common share - basic and diluted (in dollars per share)	$ 0.44	$ 0.60	$ 1.31	$ 0.72
Common Class B [Member]
Earnings per common share - basic and diluted (in dollars per share)	$ 0.47	$ 0.64	$ 1.39	$ 0.78