VAT Tax Issue in Brazil (Details Textual) In Millions, unless otherwise specified	1 Months Ended						3 Months Ended				6 Months Ended		3 Months Ended				1 Months Ended
	Oct. 31, 2010 USD ($)	Oct. 31, 2010 BRL	May 31, 2010 USD ($)	May 31, 2010 BRL	Oct. 31, 2009 USD ($)	Oct. 31, 2009 BRL	Apr. 30, 2011 USD ($)		Apr. 30, 2011 BRL		Jul. 31, 2012 USD ($)	Jul. 31, 2012 BRL	Apr. 30, 2011 Defended Based On Lapse Of Statute Limitations [Member] USD ($)	Apr. 30, 2011 Defended Based On Lapse Of Statute Limitations [Member] BRL	Apr. 30, 2011 Defended Based On State Auditor Misunderstanding [Member] USD ($)	Apr. 30, 2011 Defended Based On State Auditor Misunderstanding [Member] BRL	May 31, 2010 Original Claim 2004-2006 [Member] USD ($)	May 31, 2010 Original Claim 2004-2006 [Member] BRL	Oct. 31, 2010 Claim 2007-2009 By State Of Bahia [Member] USD ($)	Oct. 31, 2010 Claim 2007-2009 By State Of Bahia [Member] BRL
Foreign Currency Exchange Rate Translation1											1.82	1.82
Value Added Tax Examination Claims Incurred In Period					$ 3.0	4.8
Value Added Tax Examination Penalties and Interest Expense					3.5	5.6
Value Added Tax Examination Income Tax Total					6.5	10.4
Value Added Tax Claim Paid Amount			1.9	3.5
Value Added Tax Credit Carryforward Amount											1.1	2.1
Other Tax Expense (Benefit)							1.6
Value Added Tax Fines and Penalties Defendable	0.2	0.4											0.6	1.0	0.2	0.3
TotalPaid OrToBe PaidInto Government Under Amnesty Program							5.0		9.2								2.2	3.5
Value Added Tax Payable During Period	6.2	12.3																	3.1	6.2
Fines and penalties												8.0							3.0	6.1
Available For Credit	1.7	3.4					2.9	[1]	5.4	[1]
Value Added Tax Judicialdeposit												12.3
Value Added Tax Judicial Deposit To Be Paid By Pleding Asset											$ 1.6	3.1

[1] The amount allowed as credit against future payments represents the VAT taxes actually previously paid to the neighboring state.