Commitments and Contingencies (Details)	3 Months Ended								3 Months Ended			3 Months Ended
	Mar. 31, 2015 USD ($)	Mar. 31, 2015 GBP (£)	Mar. 31, 2014 USD ($)	Dec. 31, 2014 USD ($)	Mar. 31, 2015 Sentrum Portfolio USD ($)	Mar. 31, 2015 Sentrum Portfolio GBP (£)	Jul. 11, 2012 Sentrum Portfolio USD ($)	Jul. 11, 2012 Sentrum Portfolio GBP (£)	Mar. 31, 2015 29 A International Business Park USD ($)	Mar. 31, 2015 29 A International Business Park SGD	Dec. 31, 2014 29 A International Business Park USD ($)	Mar. 31, 2015 Convergence Business Park USD ($)
Commitments and Contingencies [Line Items]
Accounts payable and other accrued liabilities	$ 523,948,000			$ 605,923,000							$ 12,400,000
Additional performance based consideration earned (maximum)									36,400,000	50,000,000
Expiration of earnout contingency									November 2020	November 2020
Lease expiration period												April 2017
Sale price of building												24,000,000
Contingent liability					2,100,000	1,400,000	87,600,000	56,500,000
Real estate price, per square acre												225,000
Reduction in fair value	44,800,000	30,300,000
Change in fair value of contingent consideration	43,034,000		3,403,000
Commitments related to construction contracts	$ 124,400,000