Real Estate Acquisitions (Details) - Weighted-average amortization - Series of individually immaterial business acquisitions	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Acquired in-place leases
Business Acquisition [Line Items]
Acquired finite-lived intangible assets, weighted average useful life	14 years	7 years
Acquired above-market leases
Business Acquisition [Line Items]
Acquired finite-lived intangible assets, weighted average useful life	9 years	10 years
Acquired below-market leases
Business Acquisition [Line Items]
Acquired finite-lived intangible assets, weighted average useful life	19 years	11 years