Derivative Financial Instruments Derivative Financial Instruments (Schedule of Notional Amount and Fair Value of Open Foreign Currency Forward Contract) (Details) € in Thousands, £ in Thousands, CAD in Thousands, $ in Thousands	Dec. 31, 2016 USD ($)	Dec. 31, 2016 CAD	Dec. 31, 2016 EUR (€)	Dec. 31, 2016 GBP (£)	Dec. 31, 2015 USD ($)	Dec. 31, 2015 CAD	Dec. 31, 2015 EUR (€)	Dec. 31, 2015 GBP (£)
Financial Institution Counterparties [Member] | Other Assets [Member] | Not Designated as Hedging Instrument [Member]
Derivative Counter Party [Line Items]
Forward Contracts - Assets, Notional Amount			€ 0	£ 0			€ 1,247	£ 568
Financial Institution Counterparties [Member] | Other Liabilities [Member] | Not Designated as Hedging Instrument [Member]
Derivative Counter Party [Line Items]
Forward Contracts Liability, Notional Amount		CAD 2,214	870	£ 419		CAD 1,440	572	£ 0
Customer Counterparties [Member] | Other Assets [Member] | Not Designated as Hedging Instrument [Member]
Derivative Counter Party [Line Items]
Forward Contracts - Assets, Notional Amount		CAD 2,205	0			CAD 1,437	575
Customer Counterparties [Member] | Other Liabilities [Member] | Not Designated as Hedging Instrument [Member]
Derivative Counter Party [Line Items]
Forward Contracts Liability, Notional Amount | €			€ 0				€ 343
Eurodollar Future [Member] | Financial Institution Counterparties [Member]
Derivative Counter Party [Line Items]
Forward Contracts - Assets Estimated Fair Value	$ 0				$ 13
Forward Contracts, Liability Estimated Fair Value	(9)				(18)
Eurodollar Future [Member] | Customer Counterparties [Member]
Derivative Counter Party [Line Items]
Forward Contracts - Assets Estimated Fair Value	0				22
Forward Contracts, Liability Estimated Fair Value	0				(5)
Foreign Exchange Forward [Member] | Financial Institution Counterparties [Member]
Derivative Counter Party [Line Items]
Forward Contracts, Liability Estimated Fair Value	(21)				(5)
Foreign Exchange Forward [Member] | Customer Counterparties [Member]
Derivative Counter Party [Line Items]
Forward Contracts - Assets Estimated Fair Value	29				9
GBP Foreign Exchange Forward [Member] | Financial Institution Counterparties [Member]
Derivative Counter Party [Line Items]
Forward Contracts - Assets Estimated Fair Value	0				2
Forward Contracts, Liability Estimated Fair Value	$ (3)				$ 0