Subsequent Events (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended							12 Months Ended			0 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Feb. 03, 2014 Subsequent event
Subsequent Events
Cash dividends declared per common share (in dollars per share)	$ 0.125	$ 0.125	$ 0.125	$ 0.25	$ 0.125	$ 0.125	$ 0.125	$ 0.375	$ 0.625	$ 0.50	$ 0.125
Common stock repurchase, authorized amount											$ 50.0