Notes Payable (Details) (USD $)	12 Months Ended
	Dec. 31, 2013 instrument	Dec. 31, 2012	Jun. 30, 2012 2012 Notes	Dec. 31, 2013 2014 Notes		Dec. 31, 2013 2015 Notes		Dec. 31, 2013 2017 Notes		Dec. 31, 2013 2021 Notes		Dec. 31, 2013 2022 Notes		Dec. 31, 2013 2023 Notes		Jun. 30, 2004 Interest Rate Swap 2014 Notes	Sep. 30, 2007 Interest Rate Swap 2017 Notes	Jul. 31, 2011 Interest Rate Swap 2021 Notes derivative	Apr. 30, 2013 Forward Starting Swaps 2023 Notes derivative
Notes Payable [Line Items]
Principal			$ 50,000,000	$ 150,000,000	[1],[2],[3],[4]	$ 150,000,000	[1]	$ 250,000,000	[1],[5]	$ 300,000,000	[1],[6]	$ 325,000,000	[1]	$ 350,000,000	[1],[7]
Discount	10,816,000	9,338,000		440,000	[1],[2],[3],[4],[8]	390,000	[1],[8]	877,000	[1],[5],[8]	4,269,000	[1],[6],[8]	4,989,000	[1],[8]	2,594,000	[1],[7],[8]
Net Price				149,560,000	[1],[2],[3],[4]	149,610,000	[1]	249,123,000	[1],[5]	295,731,000	[1],[6]	320,011,000	[1]	347,406,000	[1],[7]
Stated Rate			7.75%	6.25%	[1],[2],[3],[4]	6.15%	[1]	6.875%	[1],[5]	5.50%	[1],[6]	3.80%	[1]	3.30%	[1],[7]
Effective Rate				5.91%	[1],[2],[3],[4],[9]	6.185%	[1],[9]	6.924%	[1],[5],[9]	5.69%	[1],[6],[9]	3.984%	[1],[9]	3.388%	[1],[7],[9]
Derivative, Fixed Interest Rate																4.61%
Notional amount																94,000,000	100,000,000	150,000,000	240,000
Liability amount from termination of hedge agreement																	3,260,000	5,300,000	3,000
Liability amount from termination of hedge agreement, comprehensive income																4,148,000	3,228,000	5,218,000	3,000
Number of Interest Rate Derivatives Held	0																	2	4
Debt Issuance Costs Incurred	$ 13,550,000

[1] The proceeds from the note issuance were used to pay down outstanding indebtedness of NNN’s Credit Facility.

[2] NNN plans to use proceeds from the Credit Facility and/or potential debt or equity offerings to repay the outstanding indebtedness.

[3] The proceeds from the note issuance were used to repay the obligation of the 2004 Notes.

[4] NNN entered into a forward starting interest rate swap agreement which fixed a swap rate of 4.61% on a notional amount of $94,000. Upon issuance of the 2014 Notes, NNN terminated the forward starting interest rate swap agreement resulting in a gain of $4,148. The gain has been deferred and is being amortized as an adjustment to interest expense over the term of the 2014 Notes using the effective interest method.

[5] NNN entered into an interest rate hedge with a notional amount of $100,000. Upon issuance of the 2017 Notes, NNN terminated the interest rate hedge agreement resulting in a liability of $3,260, of which $3,228 was recorded to other comprehensive income. The liability has been deferred and is being amortized as an adjustment to interest expense over the term of the 2017 Notes using the effective interest method.

[6] NNN entered into two interest rate hedges with a total notional amount of $150,000. Upon issuance of the 2021 Notes, NNN terminated the interest rate hedge agreements resulting in a liability of $5,300, of which $5,218 was deferred in other comprehensive income. The deferred liability is being amortized over the term of the note using the effective interest method.

[7] NNN entered into four forward starting swaps with an aggregate notional amount of $240,000. Upon issuance of the 2023 Notes, NNN terminated the forward starting swaps resulting in a liability of $3,156, of which $3,141 was deferred in other comprehensive income. The deferred liability is being amortized over the term of the note using the effective interest method.

[8] The note discounts are amortized to interest expense over the respective term of each debt obligation using the effective interest method.

[9] Includes the effects of the discount, treasury lock gain / loss and swap gain / loss, as applicable.