Revenues (Tables)

6 Months Ended

Jun. 30, 2018

Revenue from Contract with Customer [Abstract]

Disaggregation of Revenue

The following tables summarize revenues by segment and geography (in thousands):

	Quarter Ended June 30, 2018
	Infrastructure Solutions		Corrosion Protection		Energy Services		Total
Primary geographic region:
United States	$	117,580	$	71,386	$	77,909	$	266,875
Canada	15,607		14,819		—		30,426
Europe	12,996		2,850		—		15,846
Other foreign	14,549		7,334		—		21,883
Total revenues	$	160,732	$	96,389	$	77,909	$	335,030

	Six Months Ended June 30, 2018
	Infrastructure Solutions		Corrosion Protection		Energy Services		Total
Primary geographic region:
United States	$	211,425	$	135,245	$	170,238	$	516,908
Canada	27,876		31,389		—		59,265
Europe	26,140		5,715		—		31,855
Other foreign	29,718		22,145		—		51,863
Total revenues	$	295,159	$	194,494	$	170,238	$	659,891

	Quarter Ended June 30, 2017
	Infrastructure Solutions		Corrosion Protection		Energy Services		Total
Primary geographic region:
United States	$	106,367	$	93,693	$	78,447	$	278,507
Canada	13,417		15,870		—		29,287
Europe	14,336		3,808		—		18,144
Other foreign	14,191		14,344		—		28,535
Total revenues	$	148,311	$	127,715	$	78,447	$	354,473

	Six Months Ended June 30, 2017
	Infrastructure Solutions		Corrosion Protection		Energy Services		Total
Primary geographic region:
United States	$	200,271	$	184,596	$	151,364	$	536,231
Canada	24,233		31,881		—		56,114
Europe	27,296		6,993		—		34,289
Other foreign	25,379		27,635		—		53,014
Total revenues	$	277,179	$	251,105	$	151,364	$	679,648

The following tables summarize revenues by segment and contract type (in thousands):

	Quarter Ended June 30, 2018
	Infrastructure Solutions		Corrosion Protection		Energy Services		Total
Contract type:
Fixed fee	$	149,532	$	63,982	$	5,967	$	219,481
Time and materials	—		21,441		71,942		93,383
Product sales	11,187		10,966		—		22,153
License fees	13		—		—		13
Total revenues	$	160,732	$	96,389	$	77,909	$	335,030

	Six Months Ended June 30, 2018
	Infrastructure Solutions		Corrosion Protection		Energy Services		Total
Contract type:
Fixed fee	$	274,794	$	141,883	$	11,724	$	428,401
Time and materials	—		34,549		158,514		193,063
Product sales	20,332		18,062		—		38,394
License fees	33		—		—		33
Total revenues	$	295,159	$	194,494	$	170,238	$	659,891

	Quarter Ended June 30, 2017
	Infrastructure Solutions		Corrosion Protection		Energy Services		Total
Contract type:
Fixed fee	$	137,951	$	101,493	$	1,161	$	240,605
Time and materials	—		14,661		77,286		91,947
Product sales	10,204		11,561		—		21,765
License fees	156		—		—		156
Total revenues	$	148,311	$	127,715	$	78,447	$	354,473

	Six Months Ended June 30, 2017
	Infrastructure Solutions		Corrosion Protection		Energy Services		Total
Contract type:
Fixed fee	$	256,948	$	200,013	$	2,668	$	459,629
Time and materials	—		26,137		148,696		174,833
Product sales	19,918		24,955		—		44,873
License fees	313		—		—		313
Total revenues	$	277,179	$	251,105	$	151,364	$	679,648

Contract Asset and Liability

Net contract assets (liabilities) consisted of the following (in thousands):

	June 30,   2018			December 31, 2017
Contract assets – current	$	77,329		$	75,371
Contract liabilities – current	(43,088		)	(51,597		)
Net contract assets (liabilities)	$	34,241		$	23,774