Derivative Instruments and Hedging Activities Derivative Financial Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Liability, Fair Value, Gross Liability	$ (36,102)	$ (22,495)
Derivative Asset, Fair Value, Gross Asset	44,637	36,574
Derivative Asset, Fair Value, Gross Liability	0	0
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	44,637	36,574
Derivative Asset, Not Offset, Policy Election Deduction	(25,187)	(15,050)
Derivative, Collateral, Obligation to Return Cash	(9,918)	(7,603)
Derivative Asset, Fair Value, Amount Offset Against Collateral	9,532	13,921
Derivative Liability, Fair Value, Gross Asset	0	0
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	(36,102)	(22,495)
Derivative Liability, Not Offset, Policy Election Deduction	25,187	15,050
Derivative, Collateral, Right to Reclaim Cash	2,048	2,716
Derivative Liability, Fair Value, Amount Offset Against Collateral	(8,867)	(4,729)
Ria Operations [Member] | Foreign Exchange Contract [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, Notional Amount	251,100
Corporate Operations [Member] | Foreign Exchange Contract [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, Notional Amount	64,300
HiFX Operations [Member] | Trading Revenue [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Trading Activity, Gain	69,200	$ 72,500	$ 66,000
HiFX Operations [Member] | Foreign Exchange Contract [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, Notional Amount	$ 1,800,000
Maximum [Member] | Ria Operations [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Foreign currency forward contract term	14 days