Segment Information - Results of Operations (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Jun. 30, 2016
Segment Reporting Information [Line Items]
Gross revenues	$ 314,024	$ 325,907	$ 662,254	$ 646,396
Consolidated revenues	312,655	323,529	654,436	642,860
Gross profit	28,212	30,005	60,490	64,589
Operating income	8,237	4,935	22,538	20,036
Segment assets	635,790		635,790		$ 564,967
Goodwill	113,019		113,019		78,293
Electrical Infrastructure [Member]
Segment Reporting Information [Line Items]
Gross revenues	103,158	91,398	191,183	157,023
Consolidated revenues	103,158	91,398	191,183	157,023
Gross profit	7,225	4,021	12,475	8,729
Operating income	2,164	(723)	3,221	477
Segment assets	159,388		159,388		135,298
Goodwill	41,943		41,943		42,170
Oil Gas & Chemical [Member]
Segment Reporting Information [Line Items]
Gross revenues	56,913	63,472	94,741	132,431
Consolidated revenues	55,714	61,540	88,256	129,851
Gross profit	2,431	5,971	2,432	11,654
Operating income	(1,950)	(3,029)	(4,855)	(1,613)
Segment assets	148,095		148,095		91,350
Goodwill	42,731		42,731		14,008
Storage Solutions [Member]
Segment Reporting Information [Line Items]
Gross revenues	128,927	122,647	328,577	267,217
Consolidated revenues	128,757	122,169	328,279	266,405
Gross profit	17,071	14,426	43,524	34,658
Operating income	8,242	6,374	25,015	17,923
Segment assets	194,397		194,397		201,875
Goodwill	16,648		16,648		16,681
Industrial [Member]
Segment Reporting Information [Line Items]
Gross revenues	25,026	48,390	47,753	89,725
Consolidated revenues	25,026	48,422	46,718	89,581
Gross profit	1,485	5,587	2,059	9,548
Operating income	(219)	2,313	(843)	3,249
Segment assets	78,348		78,348		67,569
Goodwill	11,697		11,697		5,434
Other Segments [Member]
Segment Reporting Information [Line Items]
Segment assets	55,562		55,562		$ 68,875
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Gross revenues	1,369	2,378	7,818	3,536
Intersegment Eliminations [Member] | Oil Gas & Chemical [Member]
Segment Reporting Information [Line Items]
Gross revenues	1,199	1,932	6,485	2,580
Intersegment Eliminations [Member] | Storage Solutions [Member]
Segment Reporting Information [Line Items]
Gross revenues	170	478	298	812
Intersegment Eliminations [Member] | Industrial [Member]
Segment Reporting Information [Line Items]
Gross revenues	$ 0	$ (32)	$ 1,035	$ 144