Debt Senior Credit Facility (Details) (USD $)	9 Months Ended			9 Months Ended					9 Months Ended				9 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Sep. 30, 2013 Term Loan A B A-2 and A-3 and revolver [Member]	Sep. 30, 2013 Term Loan A	Sep. 30, 2013 Term Loan A2	Sep. 30, 2013 Term Loan B [Member]	Apr. 03, 2013 Term Loan B [Member]	Sep. 30, 2013 Revolver [Member]	Apr. 03, 2013 Revolver [Member]	Sep. 30, 2013 Letter of Credit	Sep. 30, 2013 Additional Revolver	Sep. 30, 2013 London Interbank Offered Rate (LIBOR) [Member] Term Loan B [Member]	Apr. 03, 2013 London Interbank Offered Rate (LIBOR) [Member] Term Loan B [Member]	Sep. 30, 2013 London Interbank Offered Rate (LIBOR) [Member] Revolver [Member]	Sep. 30, 2013 London Interbank Offered Rate (LIBOR) [Member] Maximum [Member]
Line of Credit Facility [Line Items]
Face amount								$ 300,000,000
Basis spread on variable rate					2.75%	2.75%	2.75%		2.75%				2.50%		2.50%	2.75%
Floor interest rate														0.75%
Current borrowing capacity										700,000,000
Borrowing capacity increase	350,000,000											341,800,000
Debt Issuance Cost	10,200,000
Payments of Debt Extinguishment Costs	0	14,861,000		1,100,000
Payments of Financing Costs	9,100,000
Write off unamortized debt discount	1,100,000
Write off of Deferred Debt Issuance Cost	3,300,000
Long-term Debt							299,300,000		300,000,000		58,200,000
Revolver	$ 300,000,000		$ 235,000,000
Long-term Debt, Weighted Average Interest Rate	3.00%
Total Leverage Ratio	5.75
Senior Secured Leverage Ratio	3.50
Interest Coverage Ratio	3.00