Derivative Financial Instruments (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2011	Dec. 31, 2013 Designated as Hedging Instrument [Member]	Dec. 31, 2012 Designated as Hedging Instrument [Member]	Dec. 31, 2013 Designated as Hedging Instrument [Member] Accrued Expenses And Other Current Liabilities [Member] Interest Rate Swap [Member]	Dec. 31, 2012 Designated as Hedging Instrument [Member] Accrued Expenses And Other Current Liabilities [Member] Interest Rate Swap [Member]	Dec. 31, 2013 Designated as Hedging Instrument [Member] Other Noncurrent Liabilities [Member] Interest Rate Swap [Member]	Dec. 31, 2012 Designated as Hedging Instrument [Member] Other Noncurrent Liabilities [Member] Interest Rate Swap [Member]
Interest Rate Risk [Abstract]
Term of interest rate swap (in years)	4 years
Variable interest rate (in hundredths)	1.25%
Senior credit facility balance covered under interest rate swap contracts	$ 150.0	$ 250.0
Derivatives, Fair Value [Line Items]
Fair value of derivative liability			$ 2.3	$ 4.3	$ 1.4	$ 2.3	$ 0.9	$ 2.0