Goodwill and Other Intangibles (Narratives) (Details) (USD $)	3 Months Ended		9 Months Ended			9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013	Sep. 30, 2014 Maximum	Sep. 30, 2014 Maximum Below-market ground lease	Sep. 30, 2014 Minimum	Sep. 30, 2014 CPA: 16 - Global	Mar. 31, 2014 CPA: 16 - Global	Jan. 31, 2014 CPA: 16 - Global	Sep. 30, 2014 Measurement period adjustment CPA: 16 - Global	Aug. 06, 2014 Business combination Office building in Stavanger, Norway
Finite-Lived Intangible Assets
Goodwill	$ 702,791,000		$ 702,791,000		$ 350,208,000				$ 348,876,000	$ 348,972,000	$ 348,876,000	$ (96,000)	$ 11,700,000
Finite-Lived Intangible Assets, Net
Finite lived intangible assets useful life						40 years	134 years	1 year
Amortization of intangible assets	$ 42,500,000	$ 21,700,000	$ 131,900,000	$ 64,000,000