Long Term Debt (Details Textual) (USD $)	0 Months Ended	1 Months Ended												0 Months Ended		6 Months Ended				6 Months Ended			0 Months Ended	6 Months Ended								0 Months Ended
	Feb. 14, 2013	Feb. 14, 2013	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2013 Term Loan, due 2019 [Member]		Feb. 14, 2013 Term Loan, due 2019 [Member]	Mar. 31, 2013 Senior Secured Notes due 2019 [Member]	Feb. 14, 2013 Senior Secured Notes due 2019 [Member]	Dec. 31, 2012 Old Term Loan Due 2016 [Member]	Mar. 31, 2013 Term Loan under the Credit Agreement [Member]	Feb. 14, 2013 Revolving Credit Facility [Member] Line of Credit [Member] covenants	Feb. 14, 2013 Revolving Credit Facility [Member] Letter of Credit [Member]	Feb. 14, 2013 Term Loan, due 2019 [Member] Notes Payable to Banks [Member]	Jan. 24, 2011 Term Loan, due 2019 [Member] Term Loan under the Credit Agreement [Member]	Jun. 30, 2012 Condition One [Member]	Jun. 30, 2012 Condition One [Member] Term Loan under the Credit Agreement [Member]	Jun. 30, 2012 Condition Two, Subcondition One [Member]	Jun. 30, 2012 Condition Two, Subcondition Two [Member]	Jun. 30, 2012 Condition Two, Subcondition Three [Member]	Feb. 14, 2013 Senior Secured Notes Due 2019 [Member]	Feb. 14, 2013 Senior Secured Notes Due 2019 [Member] Term Loan, due 2019 [Member]	Jan. 24, 2011 Line of Credit [Member]	Jun. 30, 2012 Line of Credit [Member]	Jun. 30, 2012 Line of Credit [Member] Years 1-3 [Member]	Feb. 14, 2013 Maximum [Member] Revolving Credit Facility [Member] Line of Credit [Member]	Feb. 14, 2013 Maximum [Member] Term Loan, due 2019 [Member] Notes Payable to Banks [Member]	Feb. 14, 2013 Minimum [Member] Revolving Credit Facility [Member] Line of Credit [Member]	Feb. 14, 2013 Minimum [Member] Term Loan, due 2019 [Member] Notes Payable to Banks [Member]	Feb. 14, 2013 Federal Funds Effective Rate [Member]	Feb. 14, 2013 London Interbank Offered Rate (LIBOR) [Member]	Feb. 14, 2013 Commitment Fee, Period One [Member] Revolving Credit Facility [Member] Line of Credit [Member]	Feb. 14, 2013 Commitment Fee, Period Two [Member] Revolving Credit Facility [Member] Line of Credit [Member]	Feb. 14, 2013 Debt Instrument, Redemption, Period Six [Member] [Member] Senior Secured Notes Due 2019 [Member] Term Loan, due 2019 [Member] Notes Payable to Banks [Member]	Feb. 15, 2013 Debt Instrument, Redemption, Period Six [Member] [Member] Senior Secured Notes Due 2019 [Member] Term Loan, due 2019 [Member] Notes Payable to Banks [Member]	Feb. 14, 2013 Mandatory Repayments, Period One [Member] Senior Secured Notes Due 2019 [Member] Term Loan, due 2019 [Member] Notes Payable to Banks [Member]	Feb. 14, 2013 Mandatory Repayments, Subsequent Periods [Member] Senior Secured Notes Due 2019 [Member] Term Loan, due 2019 [Member] Notes Payable to Banks [Member]	Feb. 15, 2013 Debt Instrument, Redemption Period Four [Member] Senior Secured Notes Due 2019 [Member] Term Loan, due 2019 [Member] Notes Payable to Banks [Member]	Feb. 15, 2013 Debt Instrument, Redemption, Period Five [Member] Senior Secured Notes Due 2019 [Member] Term Loan, due 2019 [Member] Notes Payable to Banks [Member]	Feb. 15, 2013 Debt Instrument, Redemption, Period One [Member] Senior Secured Notes Due 2019 [Member]	Jan. 24, 2011 Bank of America Syndicate [Member] Revolving Credit Facility [Member] Senior Secured Credit Facility [Member]	Jan. 24, 2011 Bank of America Syndicate [Member] Line of Credit [Member] Senior Secured Credit Facility [Member]
Long Term Debt (Textual) [Abstract]
Estimated fair value of long-term debt					$ 620,800,000			$ 294,000,000		$ 929,500,000
Debt Instrument, Unamortized Discount					19,099,000	[1]	19,400,000
Refinancing [Abstract]
Debt Instrument, Face Amount									300,000,000.0						1,000,000,000.0						300,000,000.0
Debt Instrument, Interest Rate, Stated Percentage									8.75%												8.75%					5.50%	6.25%	4.50%	5.25%
Line of Credit Facility, Amount Outstanding												75,000,000.0	40,000,000.0
Long-term Debt			940,000,000											640,000,000.0
Line of Credit Facility, Increase, Additional Borrowings														640,000,000.0
Repayments of Debt		946,500,000
Interest Paid		7,700,000
Payments of Debt Issuance Costs		32,600,000
Point in addition to base interest rate under condition																4.50%		3.50%		1.00%		1.25%								0.50%	1.00%
Debt Instrument, Fronting Fee, Percentage																												0.125%
Percentage commitment fee on average daily unused portion of exit revolving facility																								0.75%								0.50%	0.375%
Debt Instrument, Periodic Payment, Principal																																		1,600,000
Debt Instrument, Mandatory Repayments, Percentage of Excess Cash Flow																																				50.00%	25.00%
Debt Instrument, Redemption Price, Percentage																																			101.00%			103.00%	102.00%	108.75%
Debt Instruments, Retrictive Covenants, Number												2
Debt Instrument, Default Redemption, Percent of Principal																																								100.00%
Debt Instrument, Principal, Redemption Percentage, Maximum																																								35.00%
Old Credit Agreement [Abstract]
Maximum borrowing capacity																											200,000,000.0														75,000,000.0	1,075,000,000.0
Loan origination fees of Revolving Facility for future years																									1,500,000
Minimum floor interest rate on Term Loan under condition one																	2.00%
Interest rate in addition to Libor under subcondition two of condition two																			0.50%
Base interest rate under condition																LIBOR		Bank of America's prime rate		LIBOR
Debt Instrument, Annual Principal Payment			10,500,000	43,000,000
Debt Issue Costs [Abstract]
Deferred Finance Costs, Noncurrent, Gross	7,600,000	7,600,000
Amortization period	6 years 2 months 12 days																						3 years 8 months 12 days
Deferred Finance Costs, Gross																							2,400,000
Deferred Finance Costs, Noncurrent, Net			7,491,000	1,111,000
Long Term Debt (Additional Textual) [Abstract]
Weighted Average Rate of Senior Secured Credit Facility								8.75%
Variable rates of Senior Secured Credit Facility					7.50%						7.50%
Line of Credit Facility, Remaining Borrowing Capacity			61,700,000
Letter of Credit Outstanding			$ 13,300,000

[1] The $19.4 million discount, at the date of distribution, on the New Term Loan (as defined below) will be amortized using the effective interest method over the term of the senior secured credit facility due 2019.