Variable Interest Entities (Narrative) (Details) $ in Thousands		1 Months Ended	12 Months Ended
	Jan. 01, 2016 variable_interest_entity	May 31, 2015 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($) joint_venture property	Dec. 31, 2015 USD ($) property joint_venture
Variable Interest Entity [Line Items]
Number of additional VIEs to be reported | variable_interest_entity	10
Number of VIE's guaranteed by company | joint_venture				1
Carrying amount, property, net				$ 476,117	$ 240,689
Consolidated Variable Interest Entities [Member]
Variable Interest Entity [Line Items]
Number of additional VIEs to be reported | joint_venture				9	11
Number of neighborhood/community shopping centers | property				25	30
Carrying amount, property, net				$ 249,500
Joint venture amendment, additional contribution		$ 43,000
Additional contribution for capital expenditures				$ 2,500
Unconsolidated Variable Interest Entities [Member]
Variable Interest Entity [Line Items]
Number of additional VIEs to be reported | joint_venture				1	1
Number of joint venture arrangements | joint_venture				1
Future additional equity and debt contributions				$ 127,000
Scenario, Forecast [Member] | Consolidated Variable Interest Entities [Member]
Variable Interest Entity [Line Items]
Additional contribution for capital expenditures			$ 200