Derivative Instruments and Hedging Activities - Income Statement Items for Derivatives Designated as Hedging Instruments (Details 3) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income for derivatives designated as hedging instruments
Interest rate swap - cash flow hedge - ineffectiveness	$ 0
Net loss		(448)	(475)	(1,914)
Interest expense [Member] | Interest rate swap [Member] | Cash flow hedge [Member]
Income for derivatives designated as hedging instruments
Interest rate swap - cash flow hedge - interest payments		448	475	468
Interest rate swap - cash flow hedge - ineffectiveness
Interest Income [Member] | Interest rate swap [Member] | Fair Value Hedges [Member]
Income for derivatives designated as hedging instruments
Interest rate swap - cash flow hedge - interest payments				(374)
Net Loss on Interest Rate Swap [Member] | Interest rate swap [Member] | Fair Value Hedges [Member]
Income for derivatives designated as hedging instruments
Interest rate swap - fair value hedge				$ (1,072)