Derivative Financial Instruments - Fair Value of Derivative Financial Instruments and Their Classification on Balance Sheet (Details) (Interest rate contracts, USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Designated as Hedging Instrument | Other Assets
Derivatives, Fair Value [Line Items]
Asset Derivatives	$ 87	$ 137
Designated as Hedging Instrument | Other Liabilities
Derivatives, Fair Value [Line Items]
Liability Derivatives	3,547	2,650
Not Designated as Hedging Instrument | Other Assets
Derivatives, Fair Value [Line Items]
Asset Derivatives	4,764	3,730
Not Designated as Hedging Instrument | Other Liabilities
Derivatives, Fair Value [Line Items]
Liability Derivatives	$ 5,022	$ 3,887