Derivative instruments (Details Textual) (USD $)	9 Months Ended
	Mar. 31, 2013
Derivative Instruments (Textual) [Abstract]
Premiums to be paid and received under the weekly Mexican peso currency option contracts net	$ 0
Currency buy sell under contract one
Derivative Instruments (Textual) [Abstract]
Mexican peso contract: contract end date	Jul. 06, 2012
Mexican Peso Option Contract - Contractual Exchange Rate	11.85
Currency buy sell under contract two
Derivative Instruments (Textual) [Abstract]
Mexican peso contract: contract end date	Jul. 06, 2012
Mexican Peso Option Contract - Contractual Exchange Rate	12.85
Currency buy sell under contract three
Derivative Instruments (Textual) [Abstract]
Mexican Peso Option Contract - Contractual Exchange Rate	12.40
Effective period of additional Mexican peso contract	Contracts that are effective July 6, 2012 through June 28, 2013
Currency buy sell under contract four
Derivative Instruments (Textual) [Abstract]
Mexican Peso Option Contract - Contractual Exchange Rate	13.40
Effective period of additional Mexican peso contract	Contracts that are effective July 6, 2012 through June 28, 2013