Business Combinations Business Combinations (Amortization and Accretion of Intangible Assets) (Details)	12 Months Ended
	Dec. 31, 2016
In Place Leases [Member]
Business Acquisition [Line Items]
Acquired finite-lived intangible assets, weighted average useful life	18 years 4 months 24 days
Above Market Leases [Member]
Business Acquisition [Line Items]
Acquired finite-lived intangible assets, weighted average useful life	29 years 8 months 12 days
Below Market Leases [Member]
Business Acquisition [Line Items]
Acquired finite-lived intangible assets, weighted average useful life	20 years 3 months 18 days
Above Market Assumed Mortgages [Member]
Business Acquisition [Line Items]
Acquired finite-lived intangible assets, weighted average useful life	4 years 9 months 18 days