Summary of Significant Accounting Policies - Narrative (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2017 USD ($) tenant Property store shares	Mar. 31, 2016 USD ($)	Dec. 31, 2016 USD ($)
Significant Accounting Policies [Line Items]
Number of tenants | tenant	1
Number of shopping centers | store	31
Percentage of ownership in operating partnership	74.20%
Allowance for doubtful accounts receivables	$ 2,200		$ 2,000
Accounts receivable, net representing rental income accrued	$ 43,100		43,100
Period expected for the sale of property to occur	1 year
Deferred debt costs	$ 7,426		7,500
Accumulated amortization, deferred debt costs	7,600		7,300
Deferred leasing costs, net	27,761		25,983
Accumulated amortization deferred leasing cost	31,700		30,400
Amortization expense deferred leasing cost	1,300	$ 1,600
Interest capitalized	$ 769	920
Commercial development projects, availability for occupancy, maximum period after major construction activity	1 year
Depreciation expense	$ 10,000	9,500
Repairs and maintenance expense	$ 2,700	$ 4,300
Shares credited to directors' deferred fee accounts (in shares) | shares	244,008
Held-for-sale
Significant Accounting Policies [Line Items]
Number of real estate properties | Property	0
Minimum
Significant Accounting Policies [Line Items]
Allowance for doubtful accounts receivables representing rental income accrued	$ 500		$ 500
Minimum | Building
Significant Accounting Policies [Line Items]
Estimated useful life (in years)	35 years
Maximum | Building
Significant Accounting Policies [Line Items]
Estimated useful life (in years)	50 years
Maximum | Building Improvements
Significant Accounting Policies [Line Items]
Estimated useful life (in years)	20 years
Albertson's/Safeway
Significant Accounting Policies [Line Items]
Lease termination fee	$ 3,000
Giant Food
Significant Accounting Policies [Line Items]
Percentage of total revenue	4.40%
Number of shopping centers | store	10
Capital One
Significant Accounting Policies [Line Items]
Percentage of total revenue	2.70%
Number of shopping centers | store	21
Revenues
Significant Accounting Policies [Line Items]
Number of tenants | tenant	2
Percentage of total revenue	2.50%