Real Estate Investments Business Acquisitions (Details) shares in Thousands		3 Months Ended	9 Months Ended
	Mar. 01, 2017 USD ($) property shares	Sep. 30, 2017 USD ($)	Sep. 30, 2017 USD ($) shares	Sep. 30, 2016 USD ($)
Business Acquisition [Line Items]
Purchase Price			$ 37,800,000	$ 370,582,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities		$ 0	$ 0	$ 0
Concord Outparcel [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%	100.00%
Purchase Price			$ 350,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities		$ 0	0
Intangible assets		$ 0	$ 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%	100.00%
Purchase Price			$ 26,200,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities		$ 0	0
Market Common Clarendon [Member]
Business Acquisition [Line Items]
Date Purchased				May 16, 2016
Property Name				Market Common Clarendon
City/State				Arlington, VA
Business Acquisition, Percentage of Voting Interests Acquired				100.00%
Purchase Price				$ 280,500,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities				$ 0
Klahanie Shopping Center [Member]
Business Acquisition [Line Items]
Date Purchased				Jul. 15, 2016
Property Name				Klahanie Shopping Center
City/State				Sammamish, WA
Business Acquisition, Percentage of Voting Interests Acquired				100.00%
Purchase Price				$ 35,988,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities				$ 0
The Village at Tustin Legacy [Member]
Business Acquisition [Line Items]
Date Purchased				Aug. 04, 2016
Property Name				The Village at Tustin Legacy
City/State				Tustin, CA
Business Acquisition, Percentage of Voting Interests Acquired				100.00%
Purchase Price				$ 18,800,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities				$ 0
Equity One Inc. [Member]
Business Acquisition [Line Items]
Business Combination, Separately Recognized Transactions, Revenues and Gains Recognized		1,220
Number of real estate properties acquired | property	121
Shares of common stock issued for merger (in shares) | shares	65,379
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	$ 1,488,647,000
Intangible assets	$ 460,541,000
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual		$ 102,437,000	$ 238,250,000
Garden City [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%	100.00%
Purchase Price			$ 9,500,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities		$ 0	$ 0
The Market at Springwoods Village [Member]
Business Acquisition [Line Items]
Date Purchased				Mar. 04, 2016
Property Name				The Market at Springwoods Village (1)
City/State				Houston, TX
Business Acquisition, Percentage of Voting Interests Acquired				53.00%
Purchase Price				$ 17,994,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities				$ 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%	100.00%
Purchase Price			$ 0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities		$ 0	$ 0
Garden City [Member]
Business Acquisition [Line Items]
Date Purchased				Feb. 22, 2016
Property Name				Garden City Park
City/State				Garden City Park, NY
Business Acquisition, Percentage of Voting Interests Acquired				100.00%
Purchase Price				$ 17,300,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities				0
Aventura Square [Member] [Member]
Business Acquisition [Line Items]
Date Purchased			Jul. 20, 2017
Property Name			Aventura Square outparcel (4)
City/State			Miami, FL
Business Acquisition, Percentage of Voting Interests Acquired		100.00%	100.00%
Purchase Price			$ 1,750,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities		$ 0	$ 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
Partially Owned Properties [Member] | Equity One Inc. [Member]
Business Acquisition [Line Items]
Number of real estate properties acquired | property	8
Off-Market Favorable Lease [Member]
Business Acquisition [Line Items]
Intangible assets		90,000	$ 90,000	27,863,000
Off-Market Favorable Lease [Member] | Mellody Farm [Member]
Business Acquisition [Line Items]
Intangible assets		0	0
Off-Market Favorable Lease [Member] | Market Common Clarendon [Member]
Business Acquisition [Line Items]
Intangible assets				15,428,000
Off-Market Favorable Lease [Member] | Klahanie Shopping Center [Member]
Business Acquisition [Line Items]
Intangible assets				2,264,000
Off-Market Favorable Lease [Member] | The Village at Tustin Legacy [Member]
Business Acquisition [Line Items]
Intangible assets				0
Off-Market Favorable Lease [Member] | Garden City [Member]
Business Acquisition [Line Items]
Intangible assets		0	0
Off-Market Favorable Lease [Member] | The Market at Springwoods Village [Member]
Business Acquisition [Line Items]
Intangible assets				0
Off-Market Favorable Lease [Member] | Pinecrest Place [Member] [Member]
Business Acquisition [Line Items]
Intangible assets		0	0
Off-Market Favorable Lease [Member] | Garden City [Member]
Business Acquisition [Line Items]
Intangible assets				10,171,000
Off-Market Favorable Lease [Member] | Aventura Square [Member] [Member]
Business Acquisition [Line Items]
Intangible assets		90,000	90,000
Off-Market Lease, Unfavorable [Member]
Business Acquisition [Line Items]
Intangible assets		9,000	9,000	19,141,000
Off-Market Lease, Unfavorable [Member] | Mellody Farm [Member]
Business Acquisition [Line Items]
Intangible assets
Off-Market Lease, Unfavorable [Member] | Market Common Clarendon [Member]
Business Acquisition [Line Items]
Intangible assets				15,662,000
Off-Market Lease, Unfavorable [Member] | Klahanie Shopping Center [Member]
Business Acquisition [Line Items]
Intangible assets				539,000
Off-Market Lease, Unfavorable [Member] | The Village at Tustin Legacy [Member]
Business Acquisition [Line Items]
Intangible assets				0
Off-Market Lease, Unfavorable [Member] | Garden City [Member]
Business Acquisition [Line Items]
Intangible assets		0	0
Off-Market Lease, Unfavorable [Member] | The Market at Springwoods Village [Member]
Business Acquisition [Line Items]
Intangible assets				0
Off-Market Lease, Unfavorable [Member] | Pinecrest Place [Member] [Member]
Business Acquisition [Line Items]
Intangible assets		0	0
Off-Market Lease, Unfavorable [Member] | Garden City [Member]
Business Acquisition [Line Items]
Intangible assets				$ 2,940,000
Off-Market Lease, Unfavorable [Member] | Aventura Square [Member] [Member]
Business Acquisition [Line Items]
Intangible assets		9,000	$ 9,000
Operating Income (Loss) [Member] | Equity One Inc. [Member]
Business Acquisition [Line Items]
Business Combination, Separately Recognized Transactions, Revenues and Gains Recognized		(567)
Depreciation and Amortization [Member] | Equity One Inc. [Member]
Business Acquisition [Line Items]
Business Combination, Separately Recognized Transactions, Revenues and Gains Recognized		1,645
Operating Expense [Member] | Equity One Inc. [Member]
Business Acquisition [Line Items]
Business Combination, Separately Recognized Transactions, Revenues and Gains Recognized		$ 142