Note 3 - Revenues (Tables)

12 Months Ended

Dec. 31, 2020

Notes Tables

Disaggregation of Revenue [Table Text Block]

	Year Ended December 31, 2020
	Infrastructure Solutions		Corrosion Protection		Total
Geographic region:
United States	$	443,196	$	129,533	$	572,729
Canada		69,190		49,063		118,253
Europe		23,782		13,469		37,251
Other foreign		26,403		53,128		79,531
Total revenues	$	562,571	$	245,193	$	807,764

	Year Ended December 31, 2019
	Infrastructure Solutions		Corrosion Protection		Total
Geographic region:
United States	$	427,220	$	159,408	$	586,628
Canada		65,370		57,663		123,033
Europe		49,157		15,121		64,278
Other foreign		49,050		62,898		111,948
Total revenues	$	590,797	$	295,090	$	885,887

	Year Ended December 31, 2018
	Infrastructure Solutions		Corrosion Protection		Total
Geographic region:
United States	$	430,187	$	200,397	$	630,584
Canada		62,292		71,320		133,612
Europe		54,567		12,227		66,794
Other foreign		57,075		109,796		166,871
Total revenues	$	604,121	$	393,740	$	997,861

	Year Ended December 31, 2020
	Infrastructure Solutions		Corrosion Protection		Total
Contract type:
Fixed fee	$	513,187	$	162,334	$	675,521
Time and materials		—		52,713		52,713
Product sales		49,353		30,146		79,499
License fees		31		—		31
Total revenues	$	562,571	$	245,193	$	807,764

	Year Ended December 31, 2019
	Infrastructure Solutions		Corrosion Protection		Total
Contract type:
Fixed fee	$	523,042	$	203,887	$	726,929
Time and materials		—		65,084		65,084
Product sales		67,512		26,119		93,631
License fees		243		—		243
Total revenues	$	590,797	$	295,090	$	885,887

	Year Ended December 31, 2018
	Infrastructure Solutions		Corrosion Protection		Total
Contract type:
Fixed fee	$	556,642	$	296,217	$	852,859
Time and materials		—		58,372		58,372
Product sales		45,030		39,151		84,181
License fees		2,449		—		2,449
Total revenues	$	604,121	$	393,740	$	997,861

Contract Asset and Liability [Table Text Block]

	December 31,
	2020 (1)			2019 (2)
Contract assets – current	$	44,026		$	42,973
Contract liabilities – current		(37,569	)		(37,517	)
Net contract assets	$	6,457		$	5,456