Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Jun. 30, 2020
Segment Reporting Information [Line Items]
Gross revenues	$ 184,995	$ 339,180
Revenue	182,771	338,097
Gross profit (loss)	14,350	32,465
Selling, general and administrative expenses	18,128	23,691
Restructuring costs	(320)	0
Operating income	(3,458)	8,774
Segment assets	512,230		$ 517,310
Utility and Power Infrastructure [Member]
Segment Reporting Information [Line Items]
Gross revenues	60,671	47,727
Revenue	60,671	47,727
Gross profit (loss)	6,913	(168)
Selling, general and administrative expenses	2,222	2,632
Restructuring costs	11	0
Operating income	4,680	(2,800)
Segment assets	95,415		67,398
Process and Industrial Facilities
Segment Reporting Information [Line Items]
Gross revenues	46,728	155,452
Revenue	45,931	154,877
Gross profit (loss)	3,659	13,590
Selling, general and administrative expenses	4,050	6,938
Restructuring costs	(500)	0
Operating income	109	6,652
Segment assets	115,056		138,734
Storage and Terminal Solutions
Segment Reporting Information [Line Items]
Gross revenues	77,596	136,001
Revenue	76,169	135,493
Gross profit (loss)	3,778	19,742
Selling, general and administrative expenses	5,143	6,986
Restructuring costs	13	0
Operating income	(1,378)	12,756
Segment assets	180,667		187,167
Corporate [Member]
Segment Reporting Information [Line Items]
Gross profit (loss)	0	(699)
Selling, general and administrative expenses	6,713	7,135
Restructuring costs	156	0
Operating income	(6,869)	(7,834)
Segment assets	121,092		$ 124,011
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Gross revenues	2,224	1,083
Intersegment Eliminations [Member] | Process and Industrial Facilities
Segment Reporting Information [Line Items]
Gross revenues	797	575
Intersegment Eliminations [Member] | Storage and Terminal Solutions
Segment Reporting Information [Line Items]
Gross revenues	$ 1,427	$ 508