Subsequent Events (Details) (USD $)	0 Months Ended
	Feb. 10, 2015	Oct. 30, 2014	Aug. 05, 2014	May 07, 2014	Feb. 12, 2014
Subsequent Events [Abstract]
Dividends declared date	Feb. 10, 2015	Oct. 30, 2014	Aug. 05, 2014	May 07, 2014	Feb. 11, 2014
Dividend amount to be paid, per common share	$ 0.2925	$ 0.285	$ 0.2775	$ 0.27	$ 0.2625
Date dividend is payable	Mar. 09, 2015	Dec. 04, 2014	Sep. 02, 2014	Jun. 03, 2014	Mar. 10, 2014
Date shareholders must be on record for dividend	Feb. 23, 2015	Nov. 17, 2014	Aug. 18, 2014	May 19, 2014	Feb. 24, 2014