Stockholders' Equity (Details 3) (USD $)	3 Months Ended
	Aug. 31, 2012
Period One [Member]
Summary of dividend declaration and paid date
Date declared	Aug. 29, 2011
Record date	Sep. 30, 2011
Payment date	Oct. 07, 2011
Per share	$ 0.0300
Period Two [Member]
Summary of dividend declaration and paid date
Date declared	Nov. 04, 2011
Record date	Dec. 31, 2011
Payment date	Jan. 09, 2012
Per share	$ 0.0325
Period Three [Member]
Summary of dividend declaration and paid date
Date declared	Jan. 30, 2012
Record date	Mar. 30, 2012
Payment date	Apr. 06, 2012
Per share	$ 0.0325
Period Four [Member]
Summary of dividend declaration and paid date
Date declared	Apr. 30, 2012
Record date	Jun. 30, 2012
Payment date	Jul. 09, 2012
Per share	$ 0.0325
Period Five [Member]
Summary of dividend declaration and paid date
Date declared	Aug. 27, 2012
Record date	Sep. 30, 2012
Payment date	Oct. 05, 2012
Per share	$ 0.0400