Segment Information - Results of Operations (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Jun. 30, 2017
Segment Reporting Information [Line Items]
Gross revenues	$ 283,741	$ 314,024	$ 554,416	$ 662,254
Revenues	282,911	312,655	552,821	654,436
Gross profit	26,703	28,212	55,594	60,490
Operating income	5,174	8,237	12,495	22,538
Segment assets	557,866		557,866		$ 586,030
Electrical Infrastructure [Member]
Segment Reporting Information [Line Items]
Gross revenues	64,852	103,158	144,823	191,183
Revenues	64,852	103,158	144,823	191,183
Gross profit	5,541	7,225	13,808	12,475
Operating income	1,079	2,164	4,656	3,221
Segment assets	182,568		182,568		183,351
Oil Gas & Chemical [Member]
Segment Reporting Information [Line Items]
Gross revenues	88,396	56,913	174,257	94,741
Revenues	88,359	55,714	174,012	88,256
Gross profit	11,768	2,431	22,806	2,432
Operating income	5,198	(1,950)	9,332	(4,855)
Segment assets	127,278		127,278		129,177
Storage Solutions [Member]
Segment Reporting Information [Line Items]
Gross revenues	71,233	128,927	142,805	328,577
Revenues	70,441	128,757	141,456	328,279
Gross profit	5,298	17,071	12,838	43,524
Operating income	(2,609)	8,242	(2,684)	25,015
Segment assets	114,057		114,057		166,742
Industrial [Member]
Segment Reporting Information [Line Items]
Gross revenues	59,260	25,026	92,531	47,753
Revenues	59,259	25,026	92,530	46,718
Gross profit	4,096	1,485	6,142	2,059
Operating income	1,506	(219)	1,191	(843)
Segment assets	53,473		53,473		53,754
Other Segments [Member]
Segment Reporting Information [Line Items]
Segment assets	80,490		80,490		$ 53,006
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Gross revenues	830	1,369	1,595	7,818
Intersegment Eliminations [Member] | Oil Gas & Chemical [Member]
Segment Reporting Information [Line Items]
Gross revenues	37	1,199	245	6,485
Intersegment Eliminations [Member] | Storage Solutions [Member]
Segment Reporting Information [Line Items]
Gross revenues	792	170	1,349	298
Intersegment Eliminations [Member] | Industrial [Member]
Segment Reporting Information [Line Items]
Gross revenues	$ 1	$ 0	$ 1	$ 1,035