Mortgage Notes Payable, Credit Facilities and Senior Notes (Details)					12 Months Ended
	Apr. 01, 2016 USD ($)	Mar. 10, 2016 USD ($) loan	Dec. 03, 2014 USD ($)	Dec. 09, 2013 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2016 USD ($)	Jul. 26, 2016 USD ($)	Sep. 29, 2015 USD ($)	Aug. 10, 2015 USD ($)
Mortgage Notes Payable, Credit Facilities and Senior Notes [Line Items]
Number of loans assumed | loan		2
Principal repayments on mortgages					$ 7,816,000	$ 84,308,000	$ 21,982,000
Revolving Credit Facility
Mortgage Notes Payable, Credit Facilities and Senior Notes [Line Items]
Line of credit facility, maximum borrowing capacity					$ 500,000,000.0						$ 500,000,000.0
Line of credit facility, expiration date					Jan. 31, 2019
Credit facility					$ 98,000,000	135,500,000
Line of credit facility, interest rate during period (in percentage)					1.50%
Remaining borrowing capacity					$ 402,000,000
Revolving Credit Facility | Accordion Feature
Mortgage Notes Payable, Credit Facilities and Senior Notes [Line Items]
Line of credit facility, maximum borrowing capacity					$ 1,000,000,000.0
Loan Agreements
Mortgage Notes Payable, Credit Facilities and Senior Notes [Line Items]
Line of credit facility, commitment fee (in percentage)					0.20%
Line of credit, fronting fee (in percentage)					0.125%
Eurodollar | Loan Agreements
Mortgage Notes Payable, Credit Facilities and Senior Notes [Line Items]
Basis Spread on variable rate (in percentage)					1.00%
Federal Funds Rate | Loan Agreements
Mortgage Notes Payable, Credit Facilities and Senior Notes [Line Items]
Basis Spread on variable rate (in percentage)					0.50%
Term Loan Agreement
Mortgage Notes Payable, Credit Facilities and Senior Notes [Line Items]
Debt, face amount										$ 300,000,000.0
Additional borrowing capacity										$ 200,000,000
Debt Instrument, Maturity Date					Jan. 31, 2019
Interest rate during period (in percentage)					1.60%
Term Loan Agreement | Federal Funds Effective Swap Rate
Mortgage Notes Payable, Credit Facilities and Senior Notes [Line Items]
Basis Spread on variable rate (in percentage)					0.50%
Term Loan Agreement | Eurodollar
Mortgage Notes Payable, Credit Facilities and Senior Notes [Line Items]
Basis Spread on variable rate (in percentage)					1.10%
Senior Notes Due 2026
Mortgage Notes Payable, Credit Facilities and Senior Notes [Line Items]
Debt, face amount					$ 200,000,000	0			$ 200,000,000.0
Interest Rate (in percentage)									3.95%
Interest expense, debt					2,200,000
Deferred finance costs								$ 300,000
Senior Notes Due 2024
Mortgage Notes Payable, Credit Facilities and Senior Notes [Line Items]
Debt, face amount			$ 250,000,000.0
Debt Instrument, Maturity Date			Dec. 15, 2024
Interest Rate (in percentage)			4.00%
Interest expense, debt					10,000,000	10,000,000
Deferred finance costs			$ 2,200,000
Amortization of debt discount					300,000	288,000
Senior Notes Due 2023
Mortgage Notes Payable, Credit Facilities and Senior Notes [Line Items]
Debt, face amount				$ 250,000,000.0
Debt Instrument, Maturity Date				Dec. 15, 2023
Interest Rate (in percentage)				5.00%
Interest expense, debt					12,500,000	12,500,000
Deferred finance costs				$ 2,600,000
Amortization of debt discount					$ 363,000	$ 344,000
Magnolia Shopping Center
Mortgage Notes Payable, Credit Facilities and Senior Notes [Line Items]
Liabilities incurred		$ 9,300,000
Interest Rate (in percentage)					5.50%
Casitas Plaza Shopping Center
Mortgage Notes Payable, Credit Facilities and Senior Notes [Line Items]
Liabilities incurred		$ 7,600,000
Interest Rate (in percentage)					5.32%
Gateway Shopping Center WA
Mortgage Notes Payable, Credit Facilities and Senior Notes [Line Items]
Principal repayments on mortgages	$ 7,100,000