Subsequent Events (Details) (USD $)	1 Months Ended	3 Months Ended		6 Months Ended			3 Months Ended				1 Months Ended			3 Months Ended			1 Months Ended	0 Months Ended
	Jul. 31, 2013	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Jul. 02, 2013	Sep. 30, 2013 Senior Secured Notes, due 2018 [Member]	Jul. 02, 2013 Senior Secured Notes, due 2018 [Member]	Jun. 30, 2013 Senior Secured Notes, due 2018 [Member]	Dec. 31, 2012 Senior Secured Notes, due 2018 [Member]	Jul. 31, 2013 Term Loan [Member]	Jun. 30, 2013 Term Loan [Member]	Dec. 31, 2012 Term Loan [Member]	Sep. 30, 2013 Senior Subordinated Notes [Member]	Aug. 01, 2013 Senior Subordinated Notes [Member]	Mar. 10, 2010 Senior Subordinated Notes [Member]	Jul. 31, 2013 IPO Over-Allotment [Member]	Jul. 02, 2013 IPO [Member]	Aug. 01, 2013 IPO Proceeds [Member] Senior Subordinated Notes [Member]	Aug. 01, 2013 Term Loan Incremental Borrowings [Member] Senior Subordinated Notes [Member]
Subsequent Event [Line Items]
Stock Issued During Period, Shares, New Issues																	3,487,500	23,250,000
Sale of Stock, Price Per Share																	$ 17.00	$ 17.00
Proceeds from Issuance Initial Public Offering	$ 429,500,000
Net Proceeds Used For Termination Of Agreement						24,400,000
Debt Instrument, Repurchased Face Amount								175,000,000							324,000,000	28,500,000			146,000,000	178,000,000
Debt Instrument, Increase, Additional Borrowings											190,000,000
Debt, short-term and long-term								325,000,000	500,000,000	500,000,000		1,346,600,000	1,339,500,000		247,500,000
Net loss on extinguishments of long-term debt		10,300,000	0	14,200,000	9,400,000		16,700,000							24,700,000
Redemption Premium, percentage of par value								108.00%							106.268%
Extinguishment of Debt, Accrued Interest Paid to Lenders								700,000							12,000,000
Extinguishment of Debt, Fees Paid to Lenders								14,000,000							20,300,000
Write off of unamortized deferred financing costs							2,700,000							4,400,000
Litigation Settlement, Net Of Expense	10,500,000
Proceeds from Legal Settlements	$ 8,500,000