Real Estate Investments Business Acquisitions (Details) shares in Thousands, $ in Thousands		9 Months Ended
	Mar. 01, 2017 USD ($) property shares	Sep. 30, 2018 USD ($) shares	Sep. 30, 2017 USD ($)
Business Acquisition [Line Items]
Purchase Price		$ 248,463	$ 37,800
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities		$ 19,933	0
Parent Company [Member]
Business Acquisition [Line Items]
Conversion of Stock, Conversion Ratio		0.45
Shares of common stock issued for merger (in shares) | shares		65,500
Off-Market Favorable Lease [Member]
Business Acquisition [Line Items]
Intangible assets		$ 18,741	90
Off-Market Lease, Unfavorable [Member]
Business Acquisition [Line Items]
Intangible assets		$ 14,724	$ 9
Ballard Blocks I [Member]
Business Acquisition [Line Items]
Date Purchased		Jan. 02, 2018
Property Name		Ballard Blocks I
City/State		Seattle, WA
Business Acquisition, Percentage of Voting Interests Acquired		49.90%
Purchase Price		$ 54,500
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities		0
Ballard Blocks I [Member] | Off-Market Favorable Lease [Member]
Business Acquisition [Line Items]
Intangible assets		3,668
Ballard Blocks I [Member] | Off-Market Lease, Unfavorable [Member]
Business Acquisition [Line Items]
Intangible assets		$ 2,350
Ballard Blocks II [Member]
Business Acquisition [Line Items]
Date Purchased		Jan. 02, 2018
Property Name		Ballard Blocks II
City/State		Seattle, WA
Business Acquisition, Percentage of Voting Interests Acquired		49.90%
Purchase Price		$ 4,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities		0
Ballard Blocks II [Member] | Off-Market Favorable Lease [Member]
Business Acquisition [Line Items]
Intangible assets		0
Ballard Blocks II [Member] | Off-Market Lease, Unfavorable [Member]
Business Acquisition [Line Items]
Intangible assets		$ 0
Metuchen [Member]
Business Acquisition [Line Items]
Date Purchased		Jan. 05, 2018
Property Name		The District at Metuchen
City/State		Metuchen, NJ
Business Acquisition, Percentage of Voting Interests Acquired		20.00%
Purchase Price		$ 33,830
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities		0
Metuchen [Member] | Off-Market Favorable Lease [Member]
Business Acquisition [Line Items]
Intangible assets		3,147
Metuchen [Member] | Off-Market Lease, Unfavorable [Member]
Business Acquisition [Line Items]
Intangible assets		$ 1,905
Hewlett Crossing I & II [Member]
Business Acquisition [Line Items]
Date Purchased		Jan. 10, 2018
Property Name		Hewlett Crossing I & II
City/State		Hewlett, NY
Business Acquisition, Percentage of Voting Interests Acquired		100.00%
Purchase Price		$ 30,900
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities		9,700
Hewlett Crossing I & II [Member] | Off-Market Favorable Lease [Member]
Business Acquisition [Line Items]
Intangible assets		3,114
Hewlett Crossing I & II [Member] | Off-Market Lease, Unfavorable [Member]
Business Acquisition [Line Items]
Intangible assets		$ 1,868
Rivertowns [Member]
Business Acquisition [Line Items]
Date Purchased		Apr. 03, 2018
Property Name		Rivertowns Square
City/State		Dobbs Ferry, NY
Business Acquisition, Percentage of Voting Interests Acquired		100.00%
Purchase Price		$ 68,933
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities		0
Rivertowns [Member] | Off-Market Favorable Lease [Member]
Business Acquisition [Line Items]
Intangible assets		4,993
Rivertowns [Member] | Off-Market Lease, Unfavorable [Member]
Business Acquisition [Line Items]
Intangible assets		$ 5,554
Crossroad Commons II [Member]
Business Acquisition [Line Items]
Date Purchased		May 18, 2018
Property Name		Crossroads Commons II
City/State		Boulder, CO
Business Acquisition, Percentage of Voting Interests Acquired		20.00%
Purchase Price		$ 10,500
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities		0
Crossroad Commons II [Member] | Off-Market Favorable Lease [Member]
Business Acquisition [Line Items]
Intangible assets		447
Crossroad Commons II [Member] | Off-Market Lease, Unfavorable [Member]
Business Acquisition [Line Items]
Intangible assets		$ 769
Ridgewood [Member]
Business Acquisition [Line Items]
Date Purchased		Sep. 07, 2018
Property Name		Ridgewood Shopping Center
City/State		Raleigh, NC
Business Acquisition, Percentage of Voting Interests Acquired		20.00%
Purchase Price		$ 45,800
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities		10,233
Ridgewood [Member] | Off-Market Favorable Lease [Member]
Business Acquisition [Line Items]
Intangible assets		3,372
Ridgewood [Member] | Off-Market Lease, Unfavorable [Member]
Business Acquisition [Line Items]
Intangible assets		$ 2,278
The Field at Commonwealth [Member]
Business Acquisition [Line Items]
Date Purchased			Mar. 06, 2017
Property Name			The Field at Commonwealth
City/State			Chantilly, VA
Business Acquisition, Percentage of Voting Interests Acquired			100.00%
Purchase Price			$ 9,500
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities			0
The Field at Commonwealth [Member] | Off-Market Favorable Lease [Member]
Business Acquisition [Line Items]
Intangible assets			0
The Field at Commonwealth [Member] | Off-Market Lease, Unfavorable [Member]
Business Acquisition [Line Items]
Intangible assets			$ 0
Pinecrest Place [Member] [Member]
Business Acquisition [Line Items]
Date Purchased			Mar. 08, 2017
Property Name			Pinecrest Place (1)
City/State			Miami, FL
Business Acquisition, Percentage of Voting Interests Acquired			100.00%
Purchase Price			$ 0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities			0
Pinecrest Place [Member] [Member] | Off-Market Favorable Lease [Member]
Business Acquisition [Line Items]
Intangible assets			0
Pinecrest Place [Member] [Member] | Off-Market Lease, Unfavorable [Member]
Business Acquisition [Line Items]
Intangible assets			$ 0
Mellody Farm [Member]
Business Acquisition [Line Items]
Date Purchased			Apr. 13, 2017
Property Name			Mellody Farm (2)
City/State			Chicago, IL
Business Acquisition, Percentage of Voting Interests Acquired			100.00%
Purchase Price			$ 26,200
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities			0
Mellody Farm [Member] | Off-Market Favorable Lease [Member]
Business Acquisition [Line Items]
Intangible assets			0
Mellody Farm [Member] | Off-Market Lease, Unfavorable [Member]
Business Acquisition [Line Items]
Intangible assets			$ 0
Klahanie Shopping Center [Member]
Business Acquisition [Line Items]
Date Purchased			Jun. 28, 2017
Property Name			Concord outparcel (3)
City/State			Miami, FL
Business Acquisition, Percentage of Voting Interests Acquired			100.00%
Purchase Price			$ 350
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities			0
Klahanie Shopping Center [Member] | Off-Market Favorable Lease [Member]
Business Acquisition [Line Items]
Intangible assets			0
Klahanie Shopping Center [Member] | Off-Market Lease, Unfavorable [Member]
Business Acquisition [Line Items]
Intangible assets			$ 0
Aventura Square [Member]
Business Acquisition [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired			100.00%
Equity One Inc. [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	$ 1,383,291
Intangible assets	$ 458,877
Shares of common stock issued for merger (in shares) | shares	65,379
Number of real estate properties acquired | property	121
Equity One Inc. [Member] | Partially Owned Properties [Member]
Business Acquisition [Line Items]
Number of real estate properties acquired | property	8