Note 9 - Notes Payable (Details)	1 Months Ended	9 Months Ended			1 Months Ended	6 Months Ended	9 Months Ended		1 Months Ended			1 Months Ended
	May 31, 2013 USD ($)	Sep. 30, 2013 USD ($)	Sep. 30, 2012 USD ($)	Jul. 31, 2013 CAD	Oct. 23, 2013 Subsequent Event [Member] Matured October 1 [Member] USD ($)	Jun. 30, 2013 Scenario, Plan [Member] CAD	Sep. 30, 2013 Matured January 2013 [Member] USD ($)	Sep. 30, 2013 Matured June 2013 [Member] USD ($)	Mar. 31, 2013 Medium-term Notes [Member] MXN	Sep. 30, 2013 Medium-term Notes [Member] USD ($)	Sep. 30, 2013 Medium-term Notes [Member] MXN	May 31, 2013 Unsecured Debt [Member] USD ($)
Note 9 - Notes Payable (Details) [Line Items]
Debt Instrument, Term									5 years			10 years
Proceeds from Issuance of Unsecured Debt (in Pesos)		$ 621,562,000	$ 400,000,000						1,000,000,000
Debt Instrument, Basis Spread on Variable Rate									1.35%
Debt Instrument, Interest Rate, Effective Percentage									5.65%
Repayments of Notes Payable (in Pesos)									1,000,000,000
Debt Instrument, Interest Rate, Stated Percentage				3.855%	5.19%	5.18%	6.125%	4.70%	8.58%			3.125%
Long-term Debt (in Pesos)										76,900,000	1,000,000,000
Long-term Debt (in Dollars)										76,900,000	1,000,000,000
Debt Instrument, Face Amount (in Dollars and Dollars)				200,000,000								350,000,000
Proceeds from Notes Payable (in Dollars)												344,700,000
Debt Issuance Cost (in Dollars)												500,000
Repayments of Senior Debt (in Dollars)	75,000,000				100,000,000		100,000,000	75,000,000
Repayments of Medium-term Notes (in Dollars)						200,000,000