Subsequent Events (Details) (USD $)	3 Months Ended								12 Months Ended			3 Months Ended	12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Mar. 31, 2014 Subsequent Event [Member]	Dec. 31, 2013 Subsequent Event [Member]
Subsequent Event [Line Items]
Quarterly dividend paid (in dollars per share)	$ 0.15	$ 0.145	$ 0.145	$ 0.145	$ 0.145	$ 0.14	$ 0.14	$ 0.14	$ 0.585	$ 0.565	$ 0.545	$ 0.15
Dividends paid, date paid													Mar. 05, 2014
Dividends paid, record date													Feb. 15, 2014