Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020	Jun. 30, 2020
Revenue, Performance Obligation [Abstract]
Revenue, Remaining Performance Obligation, Amount	$ 444,500		$ 444,500
Performance obligations to be recognized as revenue within next twelve months	340,800		340,800
Contract with Customer, Asset and Liability [Abstract]
Costs and estimated earnings in excess of billings on uncompleted contracts	37,964		37,964		$ 59,548
Change in CIE			(21,584)
Billings on uncompleted contracts in excess of costs and estimated earnings	(59,495)		(59,495)		(63,889)
Change in BIE			4,394
Change in net contract balances			(17,190)
Contract with customer, current liability, net	(21,531)		(21,531)		(4,341)
Contract with Customer, Liability, Revenue Recognized			57,900
Disclosure Customer Contracts Additional Information [Abstract]
Construction Contractor, Receivable, Retainage, Year One	20,700		20,700		37,300
Construction Contractor, Receivable, Retainage, after Year One	3,800		3,800		$ 1,600
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer	148,260	$ 248,327	498,499	$ 905,101
Utility and Power Infrastructure [Member]
Disaggregation of Revenue [Line Items]
Loss on Contracts			8,900
Storage and Terminal Solutions
Disaggregation of Revenue [Line Items]
Loss on Contracts			3,800
Fixed-price Contract
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer	96,412	182,282	343,639	533,375
Time-and-materials Contract
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer	51,848	66,045	154,860	371,726
United States
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer	138,001	232,606	445,578	838,371
Canada
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer	8,930	12,633	47,673	58,506
Other international
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer	$ 1,329	$ 3,088	$ 5,248	$ 8,224