Note 2 - Acquisitions - Proforma Results (Details) - The 2021 Acquisitions [Member] - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenue	$ 138,741	$ 125,082	$ 252,406	$ 233,136
Net earnings	$ 7,880	$ 5,644	$ 11,309	$ 1,724
Common Class A [Member]
Earnings per Class A common share - basic and diluted (in dollars per share)	$ 0.61	$ 0.43	$ 0.87	$ 0.12
Common Class B [Member]
Earnings per Class A common share - basic and diluted (in dollars per share)	$ 0.64	$ 0.46	$ 0.92	$ 0.14