Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2012
Results of Operations
Revenues									$ 1,263,089	$ 892,574	$ 739,046
Less: Inter-segment revenues									1,263,089	892,574	739,046
Gross profit	36,903	39,944	34,150	25,476	26,999	23,126	22,333	22,244	136,473	94,702	79,618
Operating income (loss)	14,209	18,819	14,817	10,762	11,587	8,431	8,722	7,924	58,607	36,714	31,635
Segment assets	568,932				409,978				568,932	409,978	323,135
Capital expenditures									23,589	23,231	13,534
Depreciation and amortization									18,518	12,782	11,485
Electrical Infrastructure [Member]
Results of Operations
Revenues									205,570	171,204	135,086
Less: Inter-segment revenues									205,570	171,204	135,086
Gross profit									20,629	21,754	16,676
Operating income (loss)									7,703	11,185	7,609
Segment assets	120,264				64,771				120,264	64,771	51,998
Capital expenditures									9,055	2,129	2,581
Depreciation and amortization									3,292	2,167	1,823
Oil Gas & Chemical [Member]
Results of Operations
Revenues									239,690	273,848	205,823
Less: Inter-segment revenues									239,690	273,848	205,823
Gross profit									26,912	32,879	20,070
Operating income (loss)									9,939	15,415	8,134
Segment assets	72,406				75,591				72,406	75,591	53,567
Capital expenditures									5,421	2,942	2,346
Depreciation and amortization									3,768	2,943	2,838
Storage Solutions [Member]
Results of Operations
Gross profit									68,448	37,455	42,393
Operating income (loss)									34,310	11,904	17,493
Segment assets	200,493				159,149				200,493	159,149	150,543
Capital expenditures									2,519	9,929	3,929
Depreciation and amortization									7,707	6,740	6,309
Industrial [Member]
Results of Operations
Gross profit									20,484	2,614	479
Operating income (loss)									6,655	(1,790)	(1,601)
Segment assets	105,049				27,347				105,049	27,347	14,018
Capital expenditures									1,157	1,645	741
Depreciation and amortization									3,751	932	515
Unallocated Corporate [Member]
Results of Operations
Segment assets	70,720				83,120				70,720	83,120	53,009
Capital expenditures									5,437	6,586	3,937
Gross [Member]
Results of Operations
Revenues									1,264,460	895,298	741,588
Less: Inter-segment revenues									1,264,460	895,298	741,588
Gross [Member] | Electrical Infrastructure [Member]
Results of Operations
Revenues									205,570	171,204	135,086
Less: Inter-segment revenues									205,570	171,204	135,086
Gross [Member] | Oil Gas & Chemical [Member]
Results of Operations
Revenues									240,131	273,979	206,031
Less: Inter-segment revenues									240,131	273,979	206,031
Gross [Member] | Storage Solutions [Member]
Results of Operations
Revenues									611,826	395,794	380,488
Less: Inter-segment revenues									611,826	395,794	380,488
Gross [Member] | Industrial [Member]
Results of Operations
Revenues									206,933	54,321	19,983
Less: Inter-segment revenues									206,933	54,321	19,983
Industrial [Member]
Results of Operations
Revenues									206,933	54,321	19,983
Less: Inter-segment revenues									206,933	54,321	19,983
Storage Solutions [Member]
Results of Operations
Revenues									610,896	393,201	378,154
Less: Inter-segment revenues									610,896	393,201	378,154
Intersegment Eliminations [Member]
Results of Operations
Revenues									1,371	2,724	2,542
Less: Inter-segment revenues									1,371	2,724	2,542
Intersegment Eliminations [Member] | Electrical Infrastructure [Member]
Results of Operations
Revenues									0	0	0
Less: Inter-segment revenues									0	0	0
Intersegment Eliminations [Member] | Oil Gas & Chemical [Member]
Results of Operations
Revenues									441	131	208
Less: Inter-segment revenues									441	131	208
Intersegment Eliminations [Member] | Storage Solutions [Member]
Results of Operations
Revenues									930	2,593	2,334
Less: Inter-segment revenues									930	2,593	2,334
Intersegment Eliminations [Member] | Industrial [Member]
Results of Operations
Revenues										0	0
Less: Inter-segment revenues										$ 0	$ 0