Organization and Summary of Significant Accounting Policies (Summary of NNN's Investment Portfolio) (Details) ft² in Thousands	9 Months Ended
	Sep. 30, 2015 ft² state property
Property Portfolio:
Total properties | property	2,231
Gross leasable area (square feet)	24,451
States | state	47
Weighted average remaining lease term (years)	11 years 6 months