Note 7 - Contract Assets and Liabilities - Component of Contract Asset and Liability Balances (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020
Costs in excess of billings and estimated earnings	$ 59,055	$ 39,300	$ 114,378
Contract retention	126,165	125,639	112,140
Total contract assets	185,220	164,939	226,518
Billings in excess of costs and estimated earnings, net of retention	132,830	143,623	127,560
Provisions for losses	27,319	27,698	6,251
Total contract liabilities	$ 160,149	$ 171,321	$ 133,811