Acquisitions - Estimated Fair Values (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($)
Business Acquisition [Line Items]
Land and improvements	$ 120,110
Buildings and improvements (2)	259,301
Deferred leasing costs and acquisition-related intangible assets (3)	33,529
Total assets acquired	412,940
Accounts payable, accrued expenses and other liabilities	1,122
Deferred revenue and acquisition-related intangible liabilities (4)	18,050
Total liabilities assumed	19,172
Net assets and liabilities acquired	393,768
Below-market leases acquired	$ 18,100
Weighted average amortization period of below-market leases	8 years 4 months 24 days
In-place leases [Member]
Business Acquisition [Line Items]
Deferred leasing costs and acquisition-related intangible assets (3)	$ 27,100
Weighted average amortization period of above-market leases in years	3 years 10 months 24 days
Above market leases [Member]
Business Acquisition [Line Items]
Deferred leasing costs and acquisition-related intangible assets (3)	$ 600
Weighted average amortization period of above-market leases in years	15 years 9 months 18 days
Deferred leasing costs [Member]
Business Acquisition [Line Items]
Deferred leasing costs and acquisition-related intangible assets (3)	$ 5,800
Weighted average amortization period of above-market leases in years	5 years 1 month 6 days