Intangible Assets Including Goodwill - Carrying Value of Goodwill By Segment (Details) $ in Thousands	3 Months Ended
	Sep. 30, 2021 USD ($)
Goodwill [Line Items]
Goodwill	$ 60,540
Goodwill [Roll Forward]
Net balance at June 30, 2020	60,636
Translation adjustment	(96)
Net balance at September 30, 2021	60,540
Utility and Power Infrastructure [Member]
Goodwill [Line Items]
Goodwill	6,954
Goodwill [Roll Forward]
Net balance at June 30, 2020	6,984
Translation adjustment	(30)
Net balance at September 30, 2021	6,954
Process and Industrial Facilities
Goodwill [Line Items]
Goodwill	26,870
Goodwill [Roll Forward]
Net balance at June 30, 2020	26,878
Translation adjustment	(8)
Net balance at September 30, 2021	26,870
Storage and Terminal Solutions
Goodwill [Line Items]
Goodwill	26,716
Goodwill [Roll Forward]
Net balance at June 30, 2020	26,774
Translation adjustment	(58)
Net balance at September 30, 2021	$ 26,716