Subsequent Events (Details) - $ / shares	Nov. 03, 2015	Aug. 03, 2015	May. 06, 2015	Feb. 10, 2015
Subsequent Events [Abstract]
Dividends declared date	Nov. 03, 2015	Aug. 03, 2015	May 06, 2015	Feb. 10, 2015
Dividend amount to be paid, per common share	$ 0.3150	$ 0.3075	$ 0.3000	$ 0.2925
Date dividend is payable	Dec. 03, 2015	Sep. 01, 2015	Jun. 03, 2015	Mar. 09, 2015
Date shareholders must be on record for dividend	Nov. 17, 2015	Aug. 17, 2015	May 19, 2015	Feb. 23, 2015