Derivative Instruments; Fair Value (Details 2) (USD $)	3 Months Ended			6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012	Jun. 30, 2013		Jun. 30, 2012
Derivatives not designated as hedging instruments under Statement 133	Interest Rate Contracts			Interest Rate Contracts
Location of Loss Recognized in Income on Derivative	Interest Expense		Interest Expense	Interest Expense		Interest Expense
Amount of Loss Recognized in Income on Derivative	$ (4,000)	[1]	$ (16,000)	$ (9,000)	[1]	$ (51,000)

[1] Interest on fixed/variable rate variances