Subsequent Events (Details) (USD $)	0 Months Ended
	Feb. 12, 2014	Nov. 05, 2013	Aug. 07, 2013	May 07, 2013	Feb. 13, 2013
Subsequent Events [Abstract]
Dividends declared date	Feb. 11, 2014	Nov. 05, 2013	Aug. 07, 2013	May 07, 2013	Feb. 12, 2013
Dividend amount to be paid, per common share	$ 0.2625	$ 0.255	$ 0.2475	$ 0.24	$ 0.2325
Date dividend is payable	Mar. 10, 2014	Dec. 04, 2013	Sep. 03, 2013	Jun. 04, 2013	Mar. 04, 2013
Date shareholders must be on record for dividend	Feb. 24, 2014	Nov. 18, 2013	Aug. 19, 2013	May 20, 2013	Feb. 25, 2013