Organization and Summary of Significant Accounting Policies (Narrative) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Debt Instrument [Line Items]
Interest costs capitalized	$ 554,000	$ 511,000
Revolving credit facility borrowing capacity	650,000,000
Mortgages
Debt Instrument [Line Items]
Debt costs	147,000		$ 147,000
Debt costs accumulated amortization	42,000		38,000
Notes Payable to Banks
Debt Instrument [Line Items]
Debt costs	21,157,000		21,157,000
Debt costs accumulated amortization	$ 6,884,000		$ 6,376,000