Acquisitions and Dispositions (Acquisitions) (Details) $ in Thousands	1 Months Ended
	Mar. 31, 2017 store	Jan. 31, 2017 USD ($) store
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Land		$ 49,663
Building and improvements		16,779
Tenant improvements		4,611
Above-market leases		681
In-place leases		8,943
Total assets		80,677
Below-market leases		(878)
Net assets acquired		$ 79,799
Macy's
Business Acquisition [Line Items]
Number of stores closed (store) | store	3
Sears Department Stores
Business Acquisition [Line Items]
Number of stores acquired (store) | store		5
Minimum period of lease before termination		2 years
Sears Auto Centers
Business Acquisition [Line Items]
Number of stores acquired (store) | store		2
Minimum period of lease before termination		1 year
Sears Department Stores and Auto Centers
Business Acquisition [Line Items]
Consideration paid		$ 72,765
Transaction costs		$ 265
Term of lease		10 years
Initial base rent		$ 5,075
Decrease in rent for third through tenth years of leases		0.25%
Required notice period for cancellation of lease		6 months
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Land		$ 45,028
Building and improvements		14,814
Tenant improvements		4,234
Above-market leases		681
In-place leases		8,364
Total assets		73,121
Below-market leases		(356)
Net assets acquired		$ 72,765
Sears Department Stores and Auto Centers | Above-market leases
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Weighted average amortization period		2 years
Sears Department Stores and Auto Centers | In-place leases
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Weighted average amortization period		2 years 2 months
Sears Department Stores and Auto Centers | Below-market leases
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Weighted average amortization period		5 years 4 months 20 days
Jefferson Mall
Business Acquisition [Line Items]
Minimum period of lease before termination		4 years
Macy's
Business Acquisition [Line Items]
Number of stores acquired (store) | store		4
Consideration paid		$ 7,034
Transaction costs		34
Annual maintenance charge		19
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Land		4,635
Building and improvements		1,965
Tenant improvements		377
Above-market leases		0
In-place leases		579
Total assets		7,556
Below-market leases		(522)
Net assets acquired		$ 7,034
Macy's | In-place leases
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Weighted average amortization period		2 years 1 month 28 days
Macy's | Below-market leases
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Weighted average amortization period		2 years 1 month 28 days