VAT Tax Issue in Brazil and Prior Period Adjustments (Details Textual)	1 Months Ended				3 Months Ended						1 Months Ended			12 Months Ended		1 Months Ended		3 Months Ended
	Oct. 31, 2010 USD ($)	Oct. 31, 2010 BRL	May 31, 2010 USD ($)	May 31, 2010 BRL	Apr. 30, 2015 USD ($)	Apr. 30, 2015 BRL	Apr. 30, 2011 USD ($)	Jan. 31, 2015 USD ($)		Apr. 30, 2015 Discontinued Operations [Member] USD ($)	Apr. 30, 2010 Latest Tax Year [Member] BRL	Apr. 30, 2010 Tax Year 2010 [Member] USD ($)	Apr. 30, 2010 Tax Year 2015 [Member] USD ($)	Jan. 31, 2014 After State Amnesty Accepted [Member] USD ($)	Jan. 31, 2014 After State Amnesty Accepted [Member] BRL	Oct. 31, 2010 Claim 2007-2009 By State Of Bahia [Member] USD ($)	Oct. 31, 2010 Claim 2007-2009 By State Of Bahia [Member] BRL	Apr. 30, 2015 Claim December 2013 By State of Sao Paulo [Member] USD ($)	Apr. 30, 2015 Claim December 2013 By State of Sao Paulo [Member] BRL	Apr. 30, 2015 Maximum [Member]	Apr. 30, 2015 Minimum [Member]
Value Added Tax Favorable Adjustment
Value Added Tax Examination Claims Incurred In Period					$ 3,000,000	4,800,000												$ 45,000
Value Added Tax Examination Penalties and Interest Expense					3,500,000	5,600,000												200,000
Formal Judicial Process Period																				10 years	5 years
Value Added Tax Claims, Accepted Amnesty for Smaller Claim, Number of Periodic Payment																		120	120
Value Added Tax Claims, Accepted Amnesty for Smaller Claim, Periodic Payment														14,000	42,000			1,500	4,500
Value Added Tax Claims, Percentage of Abatement for Penalty and Interest														80.00%	80.00%
Value Added Tax Claims Including Penalty And Interest																		75,000	172,000
Accrued Value Added Taxes Noncurrent					130,000			60,000	[1]	2,074,371
Value Added Tax Examination Income Tax Total					6,500,000	10,400,000
Value Added Tax Claim Paid Amount			1,900,000	3,500,000
Value Added Tax Credit Carry forward Amount			1,100,000	2,100,000
Value Added Tax Judicial Tax Claim Amount					5,100,000	15,400,000
Value Added Tax Fines And Penalties																2,800,000	8,300,000
Value Added Tax Available For Credit					1,100,000	3,400,000
Value Added Tax Fines And Penalties Defendable	400,000	1,300,000
Value Added Tax Judicial deposit					2,100,000	6,200,000
Value Added Tax Payable During Period																4,900,000	14,600,000
Value Added Tax Judicial Tax Claim Percentage					20.00%	20.00%
Other Tax Expense (Benefit)							1,600,000
Value Added Tax Credit											3,400,000	1,900,000	1,300,000
Value Added Tax Favorable Adjustment					700,000
Loss Contingency, Opinion of Counsel					our attorney informs us that R$1.0 (US $0.3) million will be successfully defended based on a lapse of statute of limitations and R$0.3 (US $0.1) million based on state auditor misunderstanding	our attorney informs us that R$1.0 (US $0.3) million will be successfully defended based on a lapse of statute of limitations and R$0.3 (US $0.1) million based on state auditor misunderstanding
Value Added Tax Claim Received																$ 2,100,000	6,200,000

[1] Restated for discontinued operations.