Other Significant Events (Details) (USD $)	3 Months Ended
	Mar. 31, 2014 sqft		Mar. 31, 2013
Other Significant Noncash Transactions [Line Items]
Net Rentable Area	79,000
Lease termination fee, total contract amount	$ 5,700,000
Amortization of Intangible Assets	11,288,000		13,232,000
Lease Termination
Other Significant Noncash Transactions [Line Items]
Lease Termination Fee, amount recognized in the quarter	1,700,000
Amortization of Intangible Assets	$ 400,000	[1]

[1] The amortization of the below-market ground lease obligation is recorded as an increase to ground lease expense in the consolidated statements of operations for the periods presented.