Condensed Statements Of Income (Parenthetical) (USD $)	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013
Distributions declared	$ 2.25	[1]	$ 2.25	[2]
Dividends Declared, 3/14/2014 [Member]
Distributions declared	$ 2.25
Distributions date declared	Mar. 14, 2014
Distributions date payable	Apr. 30, 2014
Dividends Declared, 3/8/2013 [Member]
Distributions declared			$ 2.25
Distributions date declared			Mar. 08, 2013
Distributions date paid			Apr. 30, 2013

[1] $2.25 declared 3/14/2014 payable 4/30/2014

[2] $2.25 declared 3/8/2013 paid 4/30/2013