Debt (Credit Agreement) (Details) (USD $)	12 Months Ended		12 Months Ended										12 Months Ended		12 Months Ended		12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013 Other Noncurrent Assets	Dec. 31, 2013 LIBOR	Dec. 31, 2013 LIBOR Minimum	Dec. 31, 2013 LIBOR Maximum	Dec. 31, 2013 Prime Rate	Dec. 31, 2013 Prime Rate Minimum	Dec. 31, 2013 Prime Rate Maximum	Dec. 31, 2013 Unused Letters of Credit	Dec. 31, 2013 Unused Revolver	Apr. 03, 2013 Revolver	Dec. 31, 2013 Revolver LIBOR	Apr. 03, 2013 Term Loan	Dec. 31, 2013 Term Loan LIBOR	Apr. 03, 2013 Term Loan LIBOR	Dec. 31, 2013 Term Loan A B A-2 and A-3 and revolver	Dec. 31, 2013 Letter of credit	Dec. 31, 2013 Additional Revolver
Debt Instrument [Line Items]
Debt instrument, face amount														$ 300,000,000
Description of variable rate, benchmark				LIBOR			Prime Rate
Debt instrument basis spread on variable rate					1.75%	2.75%		0.75%	1.75%				2.50%		2.50%
Stated rate, minimum										1.75%	0.35%
Stated rate, maximum										2.75%	0.375%
Debt Instrument, Floor Interest Rate																0.75%
Lines of credit outstanding												700,000,000
Borrowing capacity remaining	350,000,000																		299,000,000
Debt Issuance Cost	12,300,000		11,200,000
Payment of make-whole provision and other fees for early extinguishment of debt																	1,100,000
Write Off Unamortized Debt Discount	1,100,000
Write off amount of deferred financing fees	3,300,000
Term Loans	298,500,000	563,625,000
Long-term Line of Credit	340,000,000	235,000,000
Outstanding balance	$ 1,590,534,000																	$ 61,000,000
Weighted average interest rates on outstanding borrowings	3.00%
Total Leverage Ratio	5.75
Senior Secured Leverage Ratio	3.50
Interest Coverage Ratio	3.00