Goodwill and Other Intangibles (Details 1) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014
Acquired Finite Lived Intangible Assets Liabilities
Acquired finite-lived intangible asset, acquisition	$ 1,111,446
Acquired finite-lived intangible liability, acquisition	(66,452)
Below-market rent
Acquired Finite Lived Intangible Assets Liabilities
Acquired finite lived intangible liabilities weighted average useful life	18 years 1 month 6 days
Acquired finite-lived intangible liability, acquisition	(59,740)
Above-market ground lease
Acquired Finite Lived Intangible Assets Liabilities
Acquired finite lived intangible liabilities weighted average useful life	31 years 6 months
Acquired finite-lived intangible liability, acquisition	(6,712)
In-place lease
Acquired Finite Lived Intangible Assets Liabilities
Acquired intangible assets weighted-average life	13 years 3 months 18 days
Acquired finite-lived intangible asset, acquisition	700,850
Above-market rent
Acquired Finite Lived Intangible Assets Liabilities
Acquired intangible assets weighted-average life	12 years 3 months 18 days
Acquired finite-lived intangible asset, acquisition	395,824
Below-market ground lease
Acquired Finite Lived Intangible Assets Liabilities
Acquired intangible assets weighted-average life	67 years 6 months
Acquired finite-lived intangible asset, acquisition	$ 14,772