Organization and Summary of Significant Accounting Policies (Summary of NNN's Investment Portfolio) (Details) - Jun. 30, 2015 ft² in Thousands	ft² state property
Accounting Policies [Abstract]
Total properties | property	2,138
Gross leasable area (square feet) | ft²	23,747
States	47
Weighted average remaining lease term (years)	11 years 4 months 24 days