Derivative Financial Instruments (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Expected increase to interest expense	$ 3,300,000		$ 3,300,000
Derivatives designated as cash flow hedges in accounts payable, accrued expenses and other liabilities [Abstract]
Interest rate swaps	2,047,000		2,047,000		9,369,000
Amount of unrealized gains/(losses) recognized in AOCL on derivatives (effective portion) [Abstract]
Interest rate swaps	(1,798,000)	(3,337,000)	4,801,000	(10,424,000)
Amount of (gains)/losses reclassified out of AOCL into contractual interest expense (effective portion) [Abstract]
Interest rate swaps	$ 840,000	$ 791,000	$ 2,428,000	$ 2,250,000