Goodwill and Other Intangible Assets (Narrative) (Details) - USD ($)	3 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Mar. 13, 2015
Goodwill impairment	$ 128,938,000	$ 0	$ 61,142,000	$ 80,337,000
Goodwill		19,785,000	18,932,000	81,752,000
Aggregate goodwill impairment		141,479
Impairment of finite lived intangible assets		0	59,786,000	0
Amortization expense		$ 6,992,000	9,575,000	12,245,000
Minimum
Finite lived intangible assets useful life		4 years
Maximum
Finite lived intangible assets useful life		25 years
Weighted Average
Finite lived intangible assets useful life		15 years
Rail Products and Services
Goodwill impairment			32,725,000
Goodwill		$ 14,638,000	13,785,000	48,188,000
Inspection Oilfield Services (IOS)
Goodwill impairment				69,908,000
Goodwill					$ 69,908,000
Impairment of finite lived intangible assets			42,982,000
Chemtec Energy Services, LLC
Goodwill impairment				$ 10,429,000
Impairment of finite lived intangible assets			$ 16,804,000