Segment Information (Details) - USD ($)	12 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2021
Results of Operations
Gross revenues	$ 800,878,000	$ 714,850,000	$ 679,506,000
Revenue	795,020,000	707,780,000	673,398,000
Gross profit (loss)	30,820,000	(1,206,000)	32,765,000
Selling, general and administrative expenses	68,249,000	67,690,000	69,756,000
Intangible asset impairments and restructuring costs	15,458,000	18,958,000	6,756,000
Operating income (loss)	(52,887,000)	(87,854,000)	(43,747,000)
Segment assets	400,504,000	440,793,000	467,556,000
Capital expenditures	9,009,000	3,345,000	4,354,000
Depreciation and amortization expense	13,694,000	15,254,000	17,858,000
Utility and Power Infrastructure
Results of Operations
Gross revenues	169,558,000	220,093,000	210,052,000
Revenue	169,504,000	220,093,000	210,052,000
Gross profit (loss)	10,699,000	(8,586,000)	1,506,000
Selling, general and administrative expenses	7,045,000	11,771,000	9,882,000
Intangible asset impairments and restructuring costs	37,000	2,746,000	1,312,000
Operating income (loss)	3,617,000	(23,103,000)	(9,688,000)
Segment assets	67,630,000	94,059,000	81,717,000
Capital expenditures	4,501,000	29,000	1,183,000
Depreciation and amortization expense	3,465,000	3,812,000	4,127,000
Process and Industrial Facilities
Results of Operations
Gross revenues	370,076,000	258,497,000	201,472,000
Revenue	369,823,000	254,848,000	199,917,000
Gross profit (loss)	10,756,000	9,270,000	17,642,000
Selling, general and administrative expenses	14,909,000	12,506,000	14,756,000
Intangible asset impairments and restructuring costs	13,288,000	6,867,000	3,807,000
Operating income (loss)	(17,441,000)	(10,103,000)	(921,000)
Segment assets	90,514,000	104,078,000	106,619,000
Capital expenditures	2,775,000	254,000	834,000
Depreciation and amortization expense	4,783,000	5,659,000	6,018,000
Storage and Terminal Solutions
Results of Operations
Gross revenues	261,244,000	236,260,000	267,982,000
Revenue	255,693,000	232,839,000	263,429,000
Gross profit (loss)	10,470,000	262,000	13,617,000
Selling, general and administrative expenses	20,054,000	17,284,000	18,644,000
Intangible asset impairments and restructuring costs	969,000	7,330,000	1,391,000
Operating income (loss)	(10,553,000)	(24,352,000)	(6,418,000)
Segment assets	139,333,000	141,084,000	160,782,000
Capital expenditures	1,406,000	338,000	1,136,000
Depreciation and amortization expense	3,281,000	5,540,000	7,456,000
Unallocated Corporate Costs
Results of Operations
Gross revenues	0	0	0
Revenue	0	0	0
Gross profit (loss)	(1,105,000)	(2,152,000)	0
Selling, general and administrative expenses	26,241,000	26,129,000	26,474,000
Intangible asset impairments and restructuring costs	1,164,000	2,015,000	246,000
Operating income (loss)	(28,510,000)	(30,296,000)	(26,720,000)
Segment assets	103,027,000	101,572,000	118,438,000
Capital expenditures	327,000	2,724,000	1,201,000
Depreciation and amortization expense	2,165,000	243,000	257,000
Intersegment Eliminations [Member]
Results of Operations
Gross revenues	5,858,000	7,070,000	6,108,000
Intersegment Eliminations [Member] | Utility and Power Infrastructure
Results of Operations
Gross revenues	54,000	0	0
Intersegment Eliminations [Member] | Process and Industrial Facilities
Results of Operations
Gross revenues	253,000	3,649,000	1,555,000
Intersegment Eliminations [Member] | Storage and Terminal Solutions
Results of Operations
Gross revenues	$ 5,551,000	$ 3,421,000	$ 4,553,000