Derivative Instruments and Hedging Activities (Details 1) (Designated as Hedging Instrument [Member], Cash Flow Hedging [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member]
Amount of gain (loss) recognized in accumulated other comprehensive income on interest rate derivatives (effective portion)	$ 0	$ (7)	$ 0	$ (55)
Amount of gain (loss) reclassified from accumulated other comprehensive income into income as interest expense (effective portion)	0	(107)	(58)	(176)
Amount of gain (loss) recognized in income on derivative (ineffective portion, reclassifications of missed forecasted transactions and amounts excluded from effectiveness testing)	$ 0	$ (2)	$ 0	$ (3)