Derivative Instruments and Hedging Activities Derivative Financial Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Liability, Fair Value, Gross Liability	$ (63,772)	$ (25,891)
Derivative Asset, Fair Value, Gross Asset	75,307	37,034
Derivative Asset, Fair Value, Gross Liability	0	0
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	75,307	37,034
Derivative Asset, Not Offset, Policy Election Deduction	(49,752)	(19,786)
Derivative, Collateral, Obligation to Return Cash	(7,562)	(6,415)
Derivative Asset, Fair Value, Amount Offset Against Collateral	17,993	10,833
Derivative Liability, Fair Value, Gross Asset	0	0
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	(63,772)	(25,891)
Derivative Liability, Not Offset, Policy Election Deduction	49,752	19,786
Derivative, Collateral, Right to Reclaim Cash	1,106	1,741
Derivative Liability, Fair Value, Amount Offset Against Collateral	(12,914)	(4,364)
Ria Operations [Member] | Foreign Exchange Contract [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, Notional Amount	165,100
Corporate Operations [Member] | Foreign Exchange Contract [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, Notional Amount	106,500
HiFX Operations [Member] | Trading Revenue [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Trading Activity, Gain	66,000	$ 62,800	$ 37,300
HiFX Operations [Member] | Foreign Exchange Contract [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, Notional Amount	$ 1,300,000
Maximum [Member] | Ria Operations [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Foreign currency forward contract term	14 days