401(k) Plan (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Defined Contribution Pension and Other Postretirement Plans Disclosure [Abstract]
Total expense related to 401(k) plan	$ 4.2	$ 3.5	$ 3.3