Derivative Instruments and Hedging Activities (Details 3) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Ria Operations [Member] | Foreign Currency Gain (Loss) [Member]
Derivative Instruments, Loss [Line Items]
Gain (loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments	$ 1,025	$ 1,501	$ 991	$ 348
HiFX Operations [Member] | Trading Revenue [Member]
Derivative Instruments, Loss [Line Items]
Foreign Currency Exchange Margin	$ 15,500	$ 15,900	$ 47,100	$ 23,000