Investments in Real Estate - Weighted Average Lives (Details)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Investments [Abstract]
Acquired intangible assets	24 years 9 months 18 days	10 years 10 months 2 days	16 years
Acquired intangible liabilities	51 years 8 months 12 days	8 years 3 months 22 days	5 years 7 months 18 days