Derivatives and Hedging Activities (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended	1 Months Ended					6 Months Ended
	Jun. 30, 2013	Jan. 31, 2012 Interest Rate Swap [Member]	Jun. 30, 2013 Interest Rate Swap [Member]	Jun. 30, 2013 Designated as Hedging Instrument [Member] Interest Rate Swap [Member] Accounts Payable And Other Liabilities [Member]	Dec. 31, 2012 Designated as Hedging Instrument [Member] Interest Rate Swap [Member] Accounts Payable And Other Liabilities [Member]	Jun. 30, 2013 Designated as Hedging Instrument [Member] Cash Flow Hedging [Member] Interest Rate Swap [Member]	Jun. 30, 2013 Designated as Hedging Instrument [Member] Cash Flow Hedging [Member] Interest Rate Swap [Member] Interest Expense [Member]	Jun. 30, 2012 Designated as Hedging Instrument [Member] Cash Flow Hedging [Member] Interest Rate Swap [Member] Interest Expense [Member]
Derivative [Line Items]
Derivative, Notional Amount			$ 255,000			$ 319,000
Derivative Instrument, Settlement Amount		3,539
Amount of Loss Reclassified from Accumulated OCI into Income (Effective Portion)		1,837					1,285	142
Expected Amount Of Derivative Related Interest To Be Reclassified To Interest Expense Over The Next 12 Months	3,316
Derivative, Number of Instruments Held						6
Derivative Asset				3,912
Derivative Liabilities					(6,556)
Amount of Loss Recognized in OCI on Derivatives (Effective Portion)							$ 8,851	$ (5,701)