Business Acquisitions, Goodwill and Other Intangible Assets - Goodwill (Details) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2016	Sep. 30, 2016
Goodwill [Roll Forward]
Gross Goodwill, Beginning of Period	$ 136,913
Goodwill, Impaired, Accumulated Impairment Loss, Beginning of Period	(61,576)
Goodwill, Beginning of Period	75,337
Goodwill, Period Increase (Decrease)	0
Gross Goodwill, End of Period	136,913
Goodwill, Impaired, Accumulated Impairment Loss, End of Period	(61,576)
Goodwill	75,337	$ 75,337
Power
Goodwill [Roll Forward]
Gross Goodwill, Beginning of Period	28,506
Goodwill, Impaired, Accumulated Impairment Loss, Beginning of Period	(14,506)
Goodwill, Beginning of Period	14,000
Goodwill, Period Increase (Decrease)	0
Gross Goodwill, End of Period	28,506
Goodwill, Impaired, Accumulated Impairment Loss, End of Period	(14,506)
Goodwill	14,000	14,000
Environmental
Goodwill [Roll Forward]
Gross Goodwill, Beginning of Period	40,889
Goodwill, Impaired, Accumulated Impairment Loss, Beginning of Period	(17,865)
Goodwill, Beginning of Period	23,024
Goodwill, Period Increase (Decrease)	0
Gross Goodwill, End of Period	40,889
Goodwill, Impaired, Accumulated Impairment Loss, End of Period	(17,865)
Goodwill	23,024	23,024
Infrastructure
Goodwill [Roll Forward]
Gross Goodwill, Beginning of Period	7,224
Goodwill, Impaired, Accumulated Impairment Loss, Beginning of Period	(7,224)
Goodwill, Beginning of Period	0
Goodwill, Period Increase (Decrease)	0
Gross Goodwill, End of Period	7,224
Goodwill, Impaired, Accumulated Impairment Loss, End of Period	(7,224)
Goodwill	0	0
Oil and Gas
Goodwill [Roll Forward]
Gross Goodwill, Beginning of Period	60,294
Goodwill, Impaired, Accumulated Impairment Loss, Beginning of Period	(21,981)
Goodwill, Beginning of Period	38,313
Goodwill, Period Increase (Decrease)	0
Gross Goodwill, End of Period	60,294
Goodwill, Impaired, Accumulated Impairment Loss, End of Period	(21,981)
Goodwill	$ 38,313	$ 38,313