Interest Rate Derivatives and Hedging Activities (Schedule of Derivative Instruments, Gain (Loss) in Statement of Financial Performance) (Details) (Cash Flow Hedging, Interest rate swaps, net, USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Amount of income (loss) recognized in accumulated other comprehensive income (loss) from interest rate derivatives (effective portion)	$ (1,619)	$ (656)
Amount of loss recognized in loss on derivative instruments (ineffective portion and amount excluded from effectiveness testing)	(4)	0
Interest Expense
Derivative Instruments, Gain (Loss) [Line Items]
Amount of loss reclassified from accumulated other comprehensive income (loss) into income as interest expense (effective portion)	$ (526)	$ (530)