Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 25, 2014	Sep. 26, 2013	Sep. 25, 2014	Sep. 26, 2013	Dec. 26, 2013
Income Tax Disclosure [Abstract]
Provision for income taxes	$ 2.8	$ 2.4	$ 5.3	$ 4.6
Effective tax rates (as a percent)	38.90%	38.70%	39.60%	39.30%
Valuation allowance against deferred tax assets	$ 2.4		$ 2.4		$ 2.4