Organization and Summary of Significant Accounting Policies (Narrative) (Details)	12 Months Ended
	Dec. 31, 2017 USD ($) segment	Dec. 31, 2016 USD ($) segment	Dec. 31, 2015 USD ($) segment	Oct. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)
Debt Instrument [Line Items]
Amortization of above and below Market Leases	$ 3,355,000	$ 2,842,000	$ 3,046,000
Number of segments | segment	1	1	1
Interest costs capitalized	$ 2,435,000	$ 1,738,000	$ 2,383,000
Revolving credit facility borrowing capacity	900,000,000			$ 900,000,000	$ 650,000,000
Accumulated amortization	12,667,000	11,268,000
Additional tax expense			9,607,000
In place leases amortized to expense	18,841,000	13,403,000	$ 14,380,000
Mortgages
Debt Instrument [Line Items]
Deferred costs	147,000	147,000
Accumulated amortization	55,000	38,000
Loans Payable
Debt Instrument [Line Items]
Deferred costs	22,682,000	21,157,000
Accumulated amortization	$ 6,337,000	$ 6,376,000