Business Combinations - Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands			6 Months Ended	8 Months Ended
	Jun. 30, 2018	Nov. 13, 2017	Jun. 30, 2018	Jun. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Receivables	$ 252,154		$ 252,154	$ 252,154	$ 257,425	$ 265,866
Inventories	189,571		189,571	189,571	$ 170,819	165,336
Property, plant and equipment	316,062		316,062	316,062		315,320
Total assets	929,714		929,714	929,714		902,716
Current liabilities	136,607		136,607	136,607		158,414
Total liabilities	374,991		374,991	374,991		355,236
Goodwill	44,020		44,020	44,020		$ 43,620
Well Service Group, Inc. and Utility Access Solutions, Inc. (WSG)
Business Acquisition [Line Items]
Receivables	14,527		14,527	14,527
Inventories	3,207		3,207	3,207
Other current assets	114		114	114
Property, plant and equipment	16,002		16,002	16,002
Intangible assets	26,970		26,970	26,970
Total assets	60,820		60,820	60,820
Current liabilities	7,133		7,133	7,133
Total liabilities	7,133		7,133	7,133
Net assets purchased	53,687		53,687	53,687
Goodwill	23,750		23,750	23,750
Total purchase consideration	77,437		77,437	77,437
Cash conveyed at closing in 2017		$ 44,750	$ 249	$ 45,000
Equity issued at closing in 2017		32,438
Total purchase consideration	$ 77,437	$ 77,400