Organization and Summary of Significant Accounting Policies (Narrative) (Details)	12 Months Ended
	Dec. 31, 2018 USD ($) segment	Dec. 31, 2017 USD ($) segment	Dec. 31, 2016 USD ($) segment	Oct. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)
Debt Instrument [Line Items]
Number of operating segments | segment	1	1	1
Interest costs capitalized	$ 2,675,000	$ 2,435,000	$ 1,738,000
Amortization of above and below Market Leases	2,622,000	3,355,000	2,842,000
In-place leases amortized to expense	9,209,000	18,841,000	$ 13,403,000
Revolving credit facility borrowing capacity	900,000,000			$ 900,000,000	$ 650,000,000
Deferred debt costs, accumulated amortization	14,118,000	12,667,000
Mortgages
Debt Instrument [Line Items]
Deferred debt costs	147,000	147,000
Deferred debt costs, accumulated amortization	73,000	55,000
Loans Payable
Debt Instrument [Line Items]
Deferred debt costs	26,932,000	22,682,000
Deferred debt costs, accumulated amortization	$ 6,705,000	$ 6,337,000