Dividends (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	0 Months Ended				3 Months Ended			6 Months Ended
	Apr. 25, 2013	Dec. 27, 2012	Apr. 26, 2012	Jan. 26, 2012	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	May 22, 2013	May 23, 2012	Feb. 22, 2012
Dividends, Common Stock [Abstract]
Acclerated cash dividend per share						$ 0.0425
Payment of accelerated cash dividends		$ 2.5
Board of Directors declared a cash dividend	$ 0.0425		$ 0.04	$ 0.04	$ 0.0425		$ 0.040	$ 0.0425	$ 0.8000
Payment to shareholders										$ 2.5	$ 2.5	$ 2.5