Note 7 - Contract Assets and Liabilities - Component of Contract Asset and Liability Balances (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018
Costs in excess of billings and estimated earnings	$ 127,863	$ 120,223	$ 108,105
Contract retention	106,062	99,531	105,884
Total contract assets	233,925	219,754	213,989
Billings in excess of costs and estimated earnings, net of retention	100,673	103,250	117,352
Provisions for losses	5,337	2,199	407
Total contract liabilities	$ 106,010	$ 105,449	$ 117,759