Derivative Financial Instruments (Summary of Effect of Derivative Financial Instruments on Consolidated Statements of Operations) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in OCI on Derivative (Effective Portion)	$ (2,115)	$ 5,520
Amount of Loss Reclassified from Accumulated OCI into Income (Effective Portion)	(3,065)	(2,271)
Interest Rate Contracts | Interest Expense | Derivative Assets
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in OCI on Derivative (Effective Portion)	(1,707)	2,244
Amount of Loss Reclassified from Accumulated OCI into Income (Effective Portion)	(661)	(424)
Interest Rate Contracts | Interest Expense | Derivative Liabilities
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in OCI on Derivative (Effective Portion)	(408)	3,276
Amount of Loss Reclassified from Accumulated OCI into Income (Effective Portion)	$ (2,404)	$ (1,847)