Notes Payable (Details 2) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Interest incurred and expensed on the notes payable
(Gain) loss on derivatives	$ (12,000)	$ 100,000	$ (429,000)	$ 595,000
Accretion of Senior Notes			3,000	791,000
Total interest incurred and expensed on the notes payable	18,854,000	19,312,000	53,540,000	58,100,000
Notes payable.
Interest incurred and expensed on the notes payable
Interest expense	18,130,000	18,027,000	51,747,000	53,907,000
(Gain) loss on derivatives	(12,000)	96,000	(429,000)	595,000
Accretion of Senior Notes		267,000	3,000	791,000
Amortization of deferred financing fees	736,000	922,000	2,219,000	2,804,000
Write-off of deferred financing fees				3,000
Total interest incurred and expensed on the notes payable	$ 18,854,000	$ 19,312,000	$ 53,540,000	$ 58,100,000