Real Estate Investments (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Document Fiscal Year Focus	2016
Payments to Acquire Businesses, Gross	$ 387,528,000	$ 86,657,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	$ 0	$ 42,799,000
Northgate Ph II [Member]
Business Acquisition [Line Items]
Business Acquisition, Effective Date of Acquisition		Dec. 29, 2015
Business Acquisition, Name of Acquired Entity		Northgate Ph II
Business Acquisition Location, City and State		Medford, OR
Business Acquisition, Property type		Development
Payments to Acquire Businesses, Gross		$ 4,000,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities		$ 0
University Commons [Member]
Business Acquisition [Line Items]
Business Acquisition, Effective Date of Acquisition		Sep. 01, 2015
Business Acquisition, Name of Acquired Entity		University Commons
Business Acquisition Location, City and State		Boca Raton, FL
Business Acquisition, Property type		Operating
Payments to Acquire Businesses, Gross		$ 80,500,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities		$ 42,799,000
Garden City [Member]
Business Acquisition [Line Items]
Business Acquisition, Effective Date of Acquisition	Feb. 22, 2016
Business Acquisition, Name of Acquired Entity	Garden City Park
Business Acquisition Location, City and State	Garden City Park, NY
Business Acquisition, Property type	Operating
Payments to Acquire Businesses, Gross	$ 17,300,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	$ 0
The Market at Springwoods Village [Member]
Business Acquisition [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired	53.00%
Business Acquisition, Effective Date of Acquisition	Mar. 04, 2016
Business Acquisition, Name of Acquired Entity	The Market at Springwoods Village (1)
Business Acquisition Location, City and State	Houston, TX
Business Acquisition, Property type	Development
Payments to Acquire Businesses, Gross	$ 17,994,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	0
Business Combination, Acquisition of Less than 100 Percent, Noncontrolling Interest, Fair Value	$ 8,400,000
Market Common Clarendon [Member]
Business Acquisition [Line Items]
Business Acquisition, Effective Date of Acquisition	May 16, 2016
Business Acquisition, Name of Acquired Entity	Market Common Clarendon
Business Acquisition Location, City and State	Arlington, VA
Business Acquisition, Property type	Operating
Payments to Acquire Businesses, Gross	$ 280,500,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	$ 0
Klahanie Shopping Center [Member]
Business Acquisition [Line Items]
Business Acquisition, Effective Date of Acquisition	Jul. 15, 2016
Business Acquisition, Name of Acquired Entity	Klahanie Shopping Center
Business Acquisition Location, City and State	Sammamish, WA
Business Acquisition, Property type	Operating
Payments to Acquire Businesses, Gross	$ 35,988,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	$ 0
The Village at Tustin Legacy [Member]
Business Acquisition [Line Items]
Business Acquisition, Effective Date of Acquisition	Aug. 04, 2016
Business Acquisition, Name of Acquired Entity	The Village at Tustin Legacy
Business Acquisition Location, City and State	Tustin, CA
Business Acquisition, Property type	Development
Payments to Acquire Businesses, Gross	$ 18,800,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	$ 0
Nocatee Phase III [Member]
Business Acquisition [Line Items]
Business Acquisition, Effective Date of Acquisition	Oct. 26, 2016
Business Acquisition, Name of Acquired Entity	Nocatee Phase III
Business Acquisition Location, City and State	Jacksonville, FL
Business Acquisition, Property type	Development
Payments to Acquire Businesses, Gross	$ 240,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	$ 0
Brooklyn Station Phase II [Member]
Business Acquisition [Line Items]
Business Acquisition, Effective Date of Acquisition	Oct. 30, 2016
Business Acquisition, Name of Acquired Entity	Brooklyn Station Phase II
Business Acquisition Location, City and State	Jacksonville, FL
Business Acquisition, Property type	Development
Payments to Acquire Businesses, Gross	$ 50,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	$ 0
The Village at Riverstone [Member]
Business Acquisition [Line Items]
Business Acquisition, Effective Date of Acquisition	Dec. 06, 2016
Business Acquisition, Name of Acquired Entity	The Village at Riverstone
Business Acquisition Location, City and State	Houston, TX
Business Acquisition, Property type	Development
Payments to Acquire Businesses, Gross	$ 16,656,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	0
CityLine Market Ph II [Member]
Business Acquisition [Line Items]
Business Acquisition, Effective Date of Acquisition		Oct. 09, 2015
Business Acquisition, Name of Acquired Entity		CityLine Market Ph II
Business Acquisition Location, City and State		Dallas, TX
Business Acquisition, Property type		Development
Payments to Acquire Businesses, Gross		$ 2,157,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities		0
Unconsolidated Properties [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross	92,550,000	0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	35,076,000
Off-Market Favorable Lease [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	27,863,000	64,482,000
Off-Market Favorable Lease [Member] | Northgate Ph II [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles		0
Off-Market Favorable Lease [Member] | University Commons [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles		64,482,000
Off-Market Favorable Lease [Member] | Garden City [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	10,171,000
Off-Market Favorable Lease [Member] | The Market at Springwoods Village [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	0
Off-Market Favorable Lease [Member] | Market Common Clarendon [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	15,428,000
Off-Market Favorable Lease [Member] | Klahanie Shopping Center [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	2,264,000
Off-Market Favorable Lease [Member] | The Village at Tustin Legacy [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	0
Off-Market Favorable Lease [Member] | Nocatee Phase III [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	0
Off-Market Favorable Lease [Member] | Brooklyn Station Phase II [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	0
Off-Market Favorable Lease [Member] | The Village at Riverstone [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	0
Off-Market Favorable Lease [Member] | CityLine Market Ph II [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles		0
Off-Market Favorable Lease [Member] | Unconsolidated Properties [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	6,899,000
Parent Company [Member]
Business Acquisition [Line Items]
Business Combination, Step Acquisition, Equity Interest in Acquiree, Remeasurement Gain	0	0	$ 18,271,000
Business Combination, Acquisition of Less than 100 Percent, Noncontrolling Interest, Fair Value	0	0	15,385,000
Mortgage loans assumed for the acquisition of real estate	$ 0	42,799,000	$ 103,187,000
Parent Company [Member] | Leases, Acquired-in-Place [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	7 years 4 months 24 days
Off-Market Lease, Unfavorable [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	$ 19,141,000	14,039,000
Off-Market Lease, Unfavorable [Member] | Northgate Ph II [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles		0
Off-Market Lease, Unfavorable [Member] | University Commons [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles		14,039,000
Off-Market Lease, Unfavorable [Member] | Garden City [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	2,940,000
Off-Market Lease, Unfavorable [Member] | The Market at Springwoods Village [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	0
Off-Market Lease, Unfavorable [Member] | Market Common Clarendon [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	15,662,000
Off-Market Lease, Unfavorable [Member] | Klahanie Shopping Center [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	539,000
Off-Market Lease, Unfavorable [Member] | The Village at Tustin Legacy [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	0
Off-Market Lease, Unfavorable [Member] | Nocatee Phase III [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	0
Off-Market Lease, Unfavorable [Member] | Brooklyn Station Phase II [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	0
Off-Market Lease, Unfavorable [Member] | The Village at Riverstone [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	0
Off-Market Lease, Unfavorable [Member] | CityLine Market Ph II [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles		$ 0
Off-Market Lease, Unfavorable [Member] | Unconsolidated Properties [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	$ 11,548,000