Derivative Financial Instruments - Fair Value of Derivative Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Interest Rate Swap [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative asset	$ 1,626	$ 2,032
Fair value of derivative liability	1,819	2,065
Derivatives in Hedging Relationships [Member] | Interest Rate Swap [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative asset	451	(28)
Derivatives not Designated as Hedging Instruments [Member] | Future Contracts [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative asset	(1,088)	(626)
Derivatives not Designated as Hedging Instruments [Member] | Credit Risk Participation Agreement [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative asset	3	9
Derivatives not Designated as Hedging Instruments [Member] | Credit Risk Participation Agreement [Member] | Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative liability	6	11
Derivatives not Designated as Hedging Instruments [Member] | Forward Contracts [Member] | Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative liability	237	(2,838)
Derivatives not Designated as Hedging Instruments [Member] | Interest Rate Swap [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative asset	1,175	2,060
Derivatives not Designated as Hedging Instruments [Member] | Interest Rate Swap [Member] | Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative liability	1,819	2,065
Derivatives not Designated as Hedging Instruments [Member] | Exchange Traded Purchased Options [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative asset	75	102
Derivatives not Designated as Hedging Instruments [Member] | OTC Written Options (Rate Locks) [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative asset	900	1,001
Derivatives not Designated as Hedging Instruments [Member] | Exchange Traded Written Options [Member] | Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative liability	$ 616	$ 1,174