Financial Instruments (Details Textual)	9 Months Ended
	Sep. 30, 2014 Forward Exchange Contracts, Australian [Member] USD ($)	Sep. 30, 2014 Forward Exchange Contracts, Australian [Member] AUD	Sep. 30, 2014 Forward Exchange Contracts, Canadian [Member] USD ($)	Sep. 30, 2014 Forward Exchange Contracts, Canadian [Member] CAD
Foreign Exchange Contracts At Current Value [Line Items]
Investment Owned, Foreign Currency Contract, Current Value	$ 4,400,000	4,900,000	$ 11,800,000	13,000,000
Foreign Currency Transaction Gain (Loss), Realized	$ 200,000