Derivatives and Hedging Activities Derivatives Fair Value and Balance Sheet Classification (Details) - USD ($) $ in Thousands		Jun. 30, 2018	Dec. 31, 2017
Other Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	[1]	$ 28,087	$ 19,133
Other Assets [Member] | Designated as Hedging Instrument [Member] | Interest Rate Contract [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	[1]	1,197	555
Other Assets [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contract [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	[1]	26,865	18,575
Other Assets [Member] | Not Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	[1]	1	2
Other Assets [Member] | Not Designated as Hedging Instrument [Member] | Loan Participations and Assignments [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	[1]	24	1
Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	[1]	(27,404)	(19,143)
Other Liabilities [Member] | Designated as Hedging Instrument [Member] | Interest Rate Contract [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	[1]	0	(80)
Other Liabilities [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contract [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	[1]	(27,290)	(18,953)
Other Liabilities [Member] | Not Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	[1]	(1)	(2)
Other Liabilities [Member] | Not Designated as Hedging Instrument [Member] | Loan Participations and Assignments [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	[1]	$ (113)	$ (108)

[1] For additional details, see Part I. Item 1. “Notes to Unaudited Consolidated Financial Statements - Note 5: Fair Value Measurements.”