Revenue Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Jun. 30, 2018
Revenue, Performance Obligation [Abstract]
Revenue, Remaining Performance Obligation, Amount	$ 882,400		$ 882,400
Performance obligations to be recognized as revenue within next twelve months	739,000		739,000
Contract with Customer, Asset and Liability [Abstract]
Costs and estimated earnings in excess of billings on uncompleted contracts	72,694		72,694		$ 76,632
Change in CIE			(3,938)
Billings on uncompleted contracts in excess of costs and estimated earnings	(115,366)		(115,366)		(120,740)
Change in BIE			5,374
Change in net contract balances			1,436
Contract with Customer, Liability, Revenue Recognized			94,800
Disclosure Customer Contracts Additional Information [Abstract]
Costs incurred and estimated earnings recognized on uncompleted contracts	2,089,319		2,089,319		2,081,799
Billings on uncompleted contracts	2,131,991		2,131,991		2,125,907
Total	(42,672)		(42,672)		(44,108)
Contract Receivable Retainage, Due in Next Twelve Months	21,300		21,300		25,900
Contract Receivable Retainage, Due after Next Twelve Months	11,700		11,700		$ 2,600
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	340,568	$ 282,911	659,079	$ 552,821
United States
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	329,513	259,072	639,650	480,845
Canada
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	9,714	22,996	16,795	69,855
Other international [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	$ 1,341	$ 843	$ 2,634	$ 2,121