Note 7 - Contract Assets and Liabilities - Component of Contract Asset and Liability Balances (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020
Costs in excess of billings and estimated earnings	$ 65,247	$ 39,300	$ 73,745
Contract retention	129,236	125,639	118,174
Total contract assets	194,483	164,939	191,919
Billings in excess of costs and estimated earnings, net of retention	147,072	143,623	148,050
Provisions for losses	27,778	27,698	11,768
Total contract liabilities	$ 174,850	$ 171,321	$ 159,818