Note 8 - Contract Assets and Liabilities - Component of Contract Asset and Liability Balances (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019
Costs in excess of billings and estimated earnings	$ 114,378	$ 100,761	$ 137,689
Contract retention	112,140	110,680	75,334
Total contract assets	226,518	211,441	213,023
Billings in excess of costs and estimated earnings, net of retention	127,560	86,736	91,885
Provisions for losses	6,251	9,001	12,375
Total contract liabilities	$ 133,811	$ 95,737	$ 104,260