Condensed Consolidated Statements of Operations (Unaudited) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Condensed Consolidated Statements of Operations (Unaudited) [Abstract]
Net sales	$ 200,708	$ 174,862
Cost of goods sold	168,640	127,650
Selling, general, and administrative expenses	37,720	14,801
Gain on sale of business	0	(54)
Operating (loss) income	(5,652)	32,465
Other income (expense):
Interest income	171	12
Interest expense, net of capitalized interest	(1,516)	(1,388)
Foreign exchange gain	545	1,324
Other income	115	162
(Loss) income before provision for income taxes	(6,337)	32,575
Provision for income taxes	(1,269)	11,488
Net (loss) income	(5,068)	21,087
Income attributable to noncontrolling interest, net of tax	(637)	(394)
Net (loss) income attributable to Globe Specialty Metals, Inc.	$ (5,705)	$ 20,693
Weighted average shares outstanding:
Basic (in shares)	75,050,560	75,019,481
Diluted (in shares)	75,050,560	76,788,983
Earnings per common share:
Basic (in dollars per share)	$ (0.08)	$ 0.28
Diluted (in dollars per share)	$ (0.08)	$ 0.27
Cash dividends declared per common share (in dollars per share)	$ 0.06	$ 0.20