Operating Segments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Jun. 30, 2012
Operating Segments [Abstract]
Number of reportable segments	6
Revenue from External Customer by Product Line [Abstract]
Net sales	$ 200,708	$ 174,862
Segment Reporting Information [Line Items]
Net Sales	200,708	174,862
Operating Income (Loss)	(5,652)	32,465
Income (Loss) Before Income Taxes	(6,337)	32,575
Total Assets	960,891		936,747
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	200,708	174,862
Long-lived assets	490,221		489,978
Revenue, Major Customer [Line Items]
Percentage of consolidated net sales (in hundredths)	100.00%	100.00%
Dow Corning [Member]
Revenue, Major Customer [Line Items]
Percentage of consolidated net sales (in hundredths)	21.00%	11.00%
Noncontrolling interest's ownership interest in consolidated affiliate (in hundredths)	49.00%
All other customers [Member]
Revenue, Major Customer [Line Items]
Percentage of consolidated net sales (in hundredths)	79.00%	89.00%
United States [Member]
Revenue from External Customer by Product Line [Abstract]
Net sales	156,580	154,784
Segment Reporting Information [Line Items]
Net Sales	156,580	154,784
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	156,580	154,784
Long-lived assets	329,402		330,724
Argentina [Member]
Revenue from External Customer by Product Line [Abstract]
Net sales	13,488	15,222
Segment Reporting Information [Line Items]
Net Sales	13,488	15,222
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	13,488	15,222
Long-lived assets	30,980		31,185
Canada [Member]
Revenue from External Customer by Product Line [Abstract]
Net sales	28,158	0
Segment Reporting Information [Line Items]
Net Sales	28,158	0
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	28,158	0
Long-lived assets	103,191		100,842
China [Member]
Revenue from External Customer by Product Line [Abstract]
Net sales	118	477
Segment Reporting Information [Line Items]
Net Sales	118	477
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	118	477
Long-lived assets	25,722		26,288
Poland [Member]
Revenue from External Customer by Product Line [Abstract]
Net sales	2,364	4,379
Segment Reporting Information [Line Items]
Net Sales	2,364	4,379
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	2,364	4,379
Long-lived assets	926		939
GMI [Member]
Revenue from External Customer by Product Line [Abstract]
Net sales	184,738	154,928
Segment Reporting Information [Line Items]
Net Sales	184,738	154,928
Operating Income (Loss)	23,646	35,134
Income (Loss) Before Income Taxes	23,845	34,336
Total Assets	714,082
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	184,738	154,928
Globe Metais [Member]
Revenue from External Customer by Product Line [Abstract]
Net sales	0	0
Segment Reporting Information [Line Items]
Net Sales	0	0
Operating Income (Loss)	0	(1)
Income (Loss) Before Income Taxes	0	(1)
Total Assets	0
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	0	0
Globe Metales [Member]
Revenue from External Customer by Product Line [Abstract]
Net sales	14,346	17,097
Segment Reporting Information [Line Items]
Net Sales	14,346	17,097
Operating Income (Loss)	1,439	3,517
Income (Loss) Before Income Taxes	1,164	3,147
Total Assets	86,747
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	14,346	17,097
Solsil [Member]
Revenue from External Customer by Product Line [Abstract]
Net sales	0	0
Segment Reporting Information [Line Items]
Net Sales	0	0
Operating Income (Loss)	(173)	(219)
Income (Loss) Before Income Taxes	(173)	(219)
Total Assets	29,984
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	0	0
Corporate [Member]
Revenue from External Customer by Product Line [Abstract]
Net sales	0	0
Segment Reporting Information [Line Items]
Net Sales	0	0
Operating Income (Loss)	(29,429)	(6,417)
Income (Loss) Before Income Taxes	(29,916)	(5,272)
Total Assets	455,971
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	0	0
Other [Member]
Revenue from External Customer by Product Line [Abstract]
Net sales	2,482	7,264
Segment Reporting Information [Line Items]
Net Sales	2,482	7,264
Operating Income (Loss)	(963)	(407)
Income (Loss) Before Income Taxes	(1,084)	(274)
Total Assets	39,471
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	2,482	7,264
Eliminations [Member]
Revenue from External Customer by Product Line [Abstract]
Net sales	(858)	(4,427)
Segment Reporting Information [Line Items]
Net Sales	(858)	(4,427)
Operating Income (Loss)	(172)	858
Income (Loss) Before Income Taxes	(173)	858
Total Assets	(365,364)
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	(858)	(4,427)
Silicon metal [Member]
Revenue from External Customer by Product Line [Abstract]
Net sales	112,912	89,954
Segment Reporting Information [Line Items]
Net Sales	112,912	89,954
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	112,912	89,954
Silicon based alloys [Member]
Revenue from External Customer by Product Line [Abstract]
Net sales	67,141	67,148
Segment Reporting Information [Line Items]
Net Sales	67,141	67,148
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	67,141	67,148
Other products [Member]
Revenue from External Customer by Product Line [Abstract]
Net sales	20,655	17,760
Segment Reporting Information [Line Items]
Net Sales	20,655	17,760
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ 20,655	$ 17,760