Other Assets Goodwill (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016
Goodwill [Line Items]
Goodwill	$ 318,710		$ 331,884	$ 0
Goodwill, Other Increase (Decrease)	(2,525)		0
Goodwill, Impairment Loss	(9,220)		0
Goodwill, Written off Related to Sale of Business Unit	1,929		0
Impairment of Real Estate	29,443	$ 0
Equity One Inc. [Member]
Goodwill [Line Items]
Goodwill, Purchase Accounting Adjustments	$ 500
Goodwill, Acquired During Period			$ 331,884

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of increase (decrease) from adjustments after acquisition date under purchase accounting of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of divestiture of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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The charge against earnings in the period to reduce the carrying amount of real property to fair value.

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