Financial Derivatives Derivatives in Fair Value and Cash Flow Hedging Relationships (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Line Items Presented in the Consolidated Statement of Income [Abstract]
Interest Income, Operating	$ 62,430	$ 42,522
Interest and Fee Income, Loans and Leases	45,653	36,852
Total interest expense	(76,317)	(49,546)
Gain (Loss) on Derivative Instruments, Net, Pretax	3,850	(2,486)
TotalAmountsofLineItemsPresentedintheConsolidatedStatementofIncome	27,916	32,314
Fair Value Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Fair Value Hedges Recognized in Earnings	2,838	(3,878)
Income_Expense related to interest settlements on fair value hedges	5,450	5,264
Derivative Net Hedge Ineffectiveness Gain Loss Component Recognized On Derivative	17,221	1,526
Derivative Net Hedge Ineffectiveness Gain Loss Component Recognized On Hedged Item	(14,383)	(5,404)
Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Premium_Discount recognized on hedged item	(2)	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	(267)	(512)
Derivative Net Hedge Ineffectiveness Gain Loss Component Recognized On Hedged Item	(1,780)	(652)
Unrealized Gain (Loss) on Cash Flow Hedging Instruments	(2,049)	(1,193)
Designated as Hedging Instrument [Member] | Fair Value Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Hedged Item Net Interest Settlements	7,096	8,514
Premium_Discount recognized on hedged item	(155)	(58)
Not Designated as Hedging Instrument [Member]
Line Items Presented in the Consolidated Statement of Income [Abstract]
Gain (Loss) on Derivative Instruments, Net, Pretax		(6,393)
Interest Income [Member]
Line Items Presented in the Consolidated Statement of Income [Abstract]
Gain (Loss) on Derivative Instruments, Net, Pretax	0
Interest Income [Member] | Fair Value Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Fair Value Hedges Recognized in Earnings	1,501	0
Derivative Net Hedge Ineffectiveness Gain Loss Component Recognized On Hedged Item	(18,948)
Interest Income [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Premium_Discount recognized on hedged item	0	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	0	0
Derivative Net Hedge Ineffectiveness Gain Loss Component Recognized On Hedged Item	0	0
Unrealized Gain (Loss) on Cash Flow Hedging Instruments	0	0
Interest Income [Member] | Designated as Hedging Instrument [Member] | Fair Value Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Hedged Item Net Interest Settlements	13,597	10,275
Premium_Discount recognized on hedged item	0	0
Interest Income [Member] | Not Designated as Hedging Instrument [Member]
Line Items Presented in the Consolidated Statement of Income [Abstract]
Gain (Loss) on Derivative Instruments, Net, Pretax		0
Loans and Finance Receivables [Member]
Line Items Presented in the Consolidated Statement of Income [Abstract]
Gain (Loss) on Derivative Instruments, Net, Pretax	0
Loans and Finance Receivables [Member] | Fair Value Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Fair Value Hedges Recognized in Earnings	(153)	0
Derivative Net Hedge Ineffectiveness Gain Loss Component Recognized On Hedged Item	(6,572)
Loans and Finance Receivables [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Premium_Discount recognized on hedged item	0	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	0	0
Derivative Net Hedge Ineffectiveness Gain Loss Component Recognized On Hedged Item	0	0
Unrealized Gain (Loss) on Cash Flow Hedging Instruments	0	0
Loans and Finance Receivables [Member] | Designated as Hedging Instrument [Member] | Fair Value Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Hedged Item Net Interest Settlements	1,414	516
Premium_Discount recognized on hedged item	0	0
Loans and Finance Receivables [Member] | Not Designated as Hedging Instrument [Member]
Line Items Presented in the Consolidated Statement of Income [Abstract]
Gain (Loss) on Derivative Instruments, Net, Pretax		0
Interest Expense [Member]
Line Items Presented in the Consolidated Statement of Income [Abstract]
Gain (Loss) on Derivative Instruments, Net, Pretax	0
Interest Expense [Member] | Fair Value Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Fair Value Hedges Recognized in Earnings	1,490	0
Derivative Net Hedge Ineffectiveness Gain Loss Component Recognized On Hedged Item	11,137
Interest Expense [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Premium_Discount recognized on hedged item	(2)	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	(267)	(512)
Derivative Net Hedge Ineffectiveness Gain Loss Component Recognized On Hedged Item	(1,780)	(652)
Unrealized Gain (Loss) on Cash Flow Hedging Instruments	(2,049)	(1,164)
Interest Expense [Member] | Designated as Hedging Instrument [Member] | Fair Value Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Hedged Item Net Interest Settlements	(7,915)	(2,277)
Premium_Discount recognized on hedged item	(155)	(58)
Interest Expense [Member] | Not Designated as Hedging Instrument [Member]
Line Items Presented in the Consolidated Statement of Income [Abstract]
Gain (Loss) on Derivative Instruments, Net, Pretax		0
Gain (Loss) on Derivative Instruments [Member]
Line Items Presented in the Consolidated Statement of Income [Abstract]
Gain (Loss) on Derivative Instruments, Net, Pretax	3,850	(6,393)
Gain (Loss) on Derivative Instruments [Member] | Fair Value Hedging [Member]
Line Items Presented in the Consolidated Statement of Income [Abstract]
Derivative Net Interest Settlements	0	0
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Fair Value Hedges Recognized in Earnings	0	(3,878)
Income_Expense related to interest settlements on fair value hedges	0	0
Derivative Net Hedge Ineffectiveness Gain Loss Component Recognized On Derivative	0	1,526
Derivative Net Hedge Ineffectiveness Gain Loss Component Recognized On Hedged Item	0	(5,404)
Gain (Loss) on Derivative Instruments [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Premium_Discount recognized on hedged item	0	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	0	0
Derivative Net Hedge Ineffectiveness Gain Loss Component Recognized On Hedged Item	0	0
Unrealized Gain (Loss) on Cash Flow Hedging Instruments	0	(29)
Gain (Loss) on Derivative Instruments [Member] | Designated as Hedging Instrument [Member] | Fair Value Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Hedged Item Net Interest Settlements	0	0
Premium_Discount recognized on hedged item	0	0
Interest Rate Swap [Member] | Fair Value Hedging [Member]
Line Items Presented in the Consolidated Statement of Income [Abstract]
Derivative Net Interest Settlements	(1,491)	(3,192)
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Components Included from Assessment of Interest Rate Fair Value Hedge Effectiveness		3,600
Gain (Loss) on Fair Value Hedge Ineffectiveness, Net		(300)
Interest Rate Swap [Member] | Not Designated as Hedging Instrument [Member]
Line Items Presented in the Consolidated Statement of Income [Abstract]
Gain (Loss) on Derivative Instruments, Net, Pretax	4,075	(6,684)
Interest Rate Swap [Member] | Interest Income [Member] | Fair Value Hedging [Member]
Line Items Presented in the Consolidated Statement of Income [Abstract]
Derivative Net Interest Settlements	(1,488)	(3,158)
Derivative Instruments, Gain (Loss) [Line Items]
Income_Expense related to interest settlements on fair value hedges	12,109	7,117
Derivative Net Hedge Ineffectiveness Gain Loss Component Recognized On Derivative	20,449
Interest Rate Swap [Member] | Interest Income [Member] | Not Designated as Hedging Instrument [Member]
Line Items Presented in the Consolidated Statement of Income [Abstract]
Gain (Loss) on Derivative Instruments, Net, Pretax	0	0
Interest Rate Swap [Member] | Loans and Finance Receivables [Member] | Fair Value Hedging [Member]
Line Items Presented in the Consolidated Statement of Income [Abstract]
Derivative Net Interest Settlements	(297)	(217)
Derivative Instruments, Gain (Loss) [Line Items]
Income_Expense related to interest settlements on fair value hedges	1,117	299
Derivative Net Hedge Ineffectiveness Gain Loss Component Recognized On Derivative	6,419
Interest Rate Swap [Member] | Loans and Finance Receivables [Member] | Not Designated as Hedging Instrument [Member]
Line Items Presented in the Consolidated Statement of Income [Abstract]
Gain (Loss) on Derivative Instruments, Net, Pretax	0	0
Interest Rate Swap [Member] | Interest Expense [Member] | Fair Value Hedging [Member]
Line Items Presented in the Consolidated Statement of Income [Abstract]
Derivative Net Interest Settlements	294	183
Derivative Instruments, Gain (Loss) [Line Items]
Income_Expense related to interest settlements on fair value hedges	(7,776)	(2,152)
Derivative Net Hedge Ineffectiveness Gain Loss Component Recognized On Derivative	(9,647)
Interest Rate Swap [Member] | Interest Expense [Member] | Not Designated as Hedging Instrument [Member]
Line Items Presented in the Consolidated Statement of Income [Abstract]
Gain (Loss) on Derivative Instruments, Net, Pretax	0	0
Interest Rate Swap [Member] | Gain (Loss) on Derivative Instruments [Member] | Not Designated as Hedging Instrument [Member]
Line Items Presented in the Consolidated Statement of Income [Abstract]
Gain (Loss) on Derivative Instruments, Net, Pretax	4,075	(6,684)
Forward Contracts [Member] | Not Designated as Hedging Instrument [Member]
Line Items Presented in the Consolidated Statement of Income [Abstract]
Gain (Loss) on Derivative Instruments, Net, Pretax	0	399
Forward Contracts [Member] | Interest Income [Member] | Not Designated as Hedging Instrument [Member]
Line Items Presented in the Consolidated Statement of Income [Abstract]
Gain (Loss) on Derivative Instruments, Net, Pretax	0	0
Forward Contracts [Member] | Loans and Finance Receivables [Member] | Not Designated as Hedging Instrument [Member]
Line Items Presented in the Consolidated Statement of Income [Abstract]
Gain (Loss) on Derivative Instruments, Net, Pretax	0	0
Forward Contracts [Member] | Interest Expense [Member] | Not Designated as Hedging Instrument [Member]
Line Items Presented in the Consolidated Statement of Income [Abstract]
Gain (Loss) on Derivative Instruments, Net, Pretax	0	0
Forward Contracts [Member] | Gain (Loss) on Derivative Instruments [Member] | Not Designated as Hedging Instrument [Member]
Line Items Presented in the Consolidated Statement of Income [Abstract]
Gain (Loss) on Derivative Instruments, Net, Pretax	0	399
Future [Member] | Not Designated as Hedging Instrument [Member]
Line Items Presented in the Consolidated Statement of Income [Abstract]
Gain (Loss) on Derivative Instruments, Net, Pretax	(225)	(108)
Future [Member] | Interest Income [Member] | Not Designated as Hedging Instrument [Member]
Line Items Presented in the Consolidated Statement of Income [Abstract]
Gain (Loss) on Derivative Instruments, Net, Pretax	0	0
Future [Member] | Loans and Finance Receivables [Member] | Not Designated as Hedging Instrument [Member]
Line Items Presented in the Consolidated Statement of Income [Abstract]
Gain (Loss) on Derivative Instruments, Net, Pretax	0	0
Future [Member] | Interest Expense [Member] | Not Designated as Hedging Instrument [Member]
Line Items Presented in the Consolidated Statement of Income [Abstract]
Gain (Loss) on Derivative Instruments, Net, Pretax	0	0
Future [Member] | Gain (Loss) on Derivative Instruments [Member] | Not Designated as Hedging Instrument [Member]
Line Items Presented in the Consolidated Statement of Income [Abstract]
Gain (Loss) on Derivative Instruments, Net, Pretax	$ (225)	$ (108)