Long-Term Indebtedness (Details) - USD ($)												1 Months Ended	3 Months Ended			6 Months Ended
	Oct. 15, 2017	Jun. 21, 2017	Apr. 13, 2017	Jan. 31, 2017	Dec. 20, 2016	Jun. 16, 2016	Dec. 23, 2013	Jul. 15, 2013	Dec. 21, 2012	Dec. 20, 2011	Nov. 05, 2007	Apr. 30, 2014	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Sep. 30, 2015
Summary of Long-term debt
Existing Cash Used To Retire Long-Term Debt										$ 15,000,000
Loss on debt extinguishment													$ 37,109,000		$ 2,377,000	$ 37,109,000	$ 2,377,000
Payments of Debt Issuance Costs																37,262,000	$ 5,229,000
Restricted Cash and Cash Equivalents, Current													2,784,000	$ 3,926,000		2,784,000
Interest Rate Swap [Member]
Summary of Long-term debt
Derivative, Notional Amount												$ 200,000,000.0
Credit Facility Amendment 2013 [Member]
Summary of Long-term debt
Excess Cash Available for General Corporate Purposes							$ 200,000,000
Credit Facility 2011 [Member]
Summary of Long-term debt
Debt Instrument, Face Amount										$ 1,135,000,000.0
Credit Facility 2011 - Revolving Loan [Member]
Summary of Long-term debt
Debt Instrument, Term										5 years
Line of Credit Facility, Maximum Borrowing Capacity										$ 200,000,000.0
Credit Facility 2011 - Term Loans [Member]
Summary of Long-term debt
Proceeds from Issuance of Debt Utilized for Extinguishment of Existing Debt Instruments										935,000,000.0
Credit Facility 2011 - Term Loan A [Member]
Summary of Long-term debt
Debt Instrument, Face Amount										$ 75,000,000.0
Debt Instrument, Term										5 years
Extinguishment of Debt, Amount									$ 72,200,000
Credit Facility 2011 - Term Loan B [Member]
Summary of Long-term debt
Debt Instrument, Face Amount										$ 860,000,000.0
Debt Instrument, Term										7 years
Line of Credit Facility, Additional Contingent Borrowing Capacity										$ 300,000,000
Extinguishment of Debt, Amount									$ 277,800,000
Debt Instrument, Basis Spread on Variable Rate										3.00%
Debt Instrument, Interest Rate, Effective Percentage														3.16%
Credit Facility 2011 - Term Loan B [Member] | London Interbank Offered Rate (LIBOR) [Member]
Summary of Long-term debt
Debt Instrument, Description of Variable Rate Basis										LIBOR
Interest rate, variable interest rate floor (as a percent)										1.00%
Credit Facility 2011 - Term Loan B [Member] | Credit Facility Amendment 2012 [Member]
Summary of Long-term debt
Debt Amendment, Interest Rate Reduction									0.25%
Credit Facility 2011 - Term Loan B [Member] | Credit Facility Amendment 2013 [Member]
Summary of Long-term debt
Debt Amendment, Interest Rate Reduction							0.50%
Credit Facility 2011 - Term Loan B [Member] | Credit Facility Amendment 2013 [Member] | Variable Rate Basis Spread [Member]
Summary of Long-term debt
Debt Amendment, Interest Rate Reduction							0.25%
Credit Facility 2011 - Term Loan B [Member] | Credit Facility Amendment 2013 [Member] | LIBOR Floor [Member]
Summary of Long-term debt
Debt Amendment, Interest Rate Reduction							0.25%
Credit Facility 2011 - Term Loan B, As Amended 2013 [Member]
Summary of Long-term debt
Extinguishment of Debt, Amount																150,000,000
Debt Instrument, Basis Spread on Variable Rate							2.75%
Interest rate, variable interest rate floor (as a percent)						0.75%
Credit Facility 2011 - Term Loan B, As Amended 2013 [Member] | London Interbank Offered Rate (LIBOR) [Member]
Summary of Long-term debt
Debt Instrument, Description of Variable Rate Basis							LIBOR					LIBOR
Interest rate, variable interest rate floor (as a percent)							0.75%
Credit Facility 2011 - Term Loan B, As Amended 2013 [Member] | Credit Facility Amendment 2015 [Member] | Variable Rate Basis Spread [Member]
Summary of Long-term debt
Debt Amendment, Interest Rate Reduction						0.25%
Credit Facility 2011 - Term Loan B, As Amended 2015 [Member]
Summary of Long-term debt
Extinguishment of Debt, Amount						$ 150,000,000
Debt Instrument, Basis Spread on Variable Rate						2.50%
Loss on debt extinguishment															$ 2,400,000
Payments of Debt Issuance Costs						$ 1,000,000
Credit Facility 2011 - Term Loan B, As Amended 2015 [Member] | London Interbank Offered Rate (LIBOR) [Member]
Summary of Long-term debt
Debt Instrument, Description of Variable Rate Basis						LIBOR
Credit Facility 2011 - Term Loan B, As Amended 2015 [Member] | Credit Facility Amendment 2016 June [Member] | Variable Rate Basis Spread [Member]
Summary of Long-term debt
Debt Amendment, Interest Rate Reduction					0.25%
Credit Facility 2011 - Term Loan B, As Amended 2015 [Member] | Credit Facility Amendment 2016 December [Member] | Variable Rate Basis Spread [Member]
Summary of Long-term debt
Debt Amendment, Interest Rate Reduction		0.25%
Credit Facility 2011 - Term Loan B, As Amended 2016 June [Member]
Summary of Long-term debt
Debt Instrument, Basis Spread on Variable Rate					2.25%
Loss on debt extinguishment														$ 500,000
Credit Facility 2011 - Term Loan B, As Amended 2016 June [Member] | London Interbank Offered Rate (LIBOR) [Member]
Summary of Long-term debt
Debt Instrument, Description of Variable Rate Basis					LIBOR
Credit Facility 2011 - Term Loan B, As Amended 2016 December [Member]
Summary of Long-term debt
Debt Instrument, Basis Spread on Variable Rate					2.00%
Debt Instrument, Description of Variable Rate Basis					LIBOR
Loss on debt extinguishment													200,000
Payments of Debt Issuance Costs		$ 500,000
Old Debt - First Lien Amendment [Member]
Summary of Long-term debt
Extinguishment of Debt, Amount										$ 950,000,000
Amended and Restated Revolving Loan [Member]
Summary of Long-term debt
Line of Credit Facility, Maximum Borrowing Capacity																		$ 250,000,000.0
Long-term Line of Credit													0	0		0
Letters of Credit Outstanding, Amount													19,687,000	19,687,000		$ 19,687,000
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage																0.375%	0.375%
Amended and Restated Revolving Loan [Member] | London Interbank Offered Rate (LIBOR) [Member]
Summary of Long-term debt
Debt Instrument, Description of Variable Rate Basis						LIBOR
Debt Instrument, Frequency of Periodic Payment						annual
Amended and Restated Term Loan B [Member]
Summary of Long-term debt
Debt Instrument, Face Amount																		$ 700,000,000.0
Line of Credit Facility, Additional Contingent Borrowing Capacity													350,000,000.0			$ 350,000,000.0
Debt Instrument, Frequency of Periodic Payment						annual										quarterly
Long-term Debt, Gross													$ 544,750,000	544,750,000		$ 544,750,000
Debt Instrument, Interest Rate, Effective Percentage													3.15%			3.15%
Debt Instrument, Periodic Payment																$ 1,800,000
Amended and Restated Term Loan B [Member] | London Interbank Offered Rate (LIBOR) [Member]
Summary of Long-term debt
Debt Instrument, Description of Variable Rate Basis						LIBOR
Senior Unsecured 2021 Notes [Member]
Summary of Long-term debt
Debt Instrument, Face Amount									$ 800,000,000.0
Proceeds from Issuance of Debt Utilized for Extinguishment of Existing Debt Instruments									350,000,000
Proceeds from Issuance of Debt Utilized for Share Repurchases and Other Corporate Matters									$ 450,000,000
Loss on debt extinguishment													$ 36,900,000
Debt Instrument, Frequency of Periodic Payment									semi-annual
Long-term Debt, Gross													0	800,000,000		0
Debt Instrument, Interest Rate, Stated Percentage									5.25%
Periodic payment of interest								$ 22,300,000	$ 21,000,000
Senior Unsecured 2024 Notes [Member]
Summary of Long-term debt
Debt Instrument, Face Amount						$ 300,000,000.0
Payments of Debt Issuance Costs						$ 4,700,000
Debt Instrument, Frequency of Periodic Payment						semi-annually
Long-term Debt, Gross													1,000,000,000	300,000,000		1,000,000,000
Debt Instrument, Interest Rate, Stated Percentage						4.875%
Periodic payment of interest			$ 24,400,000	$ 9,100,000
Senior Unsecured 2024 Notes Add-on [Member]
Summary of Long-term debt
Debt Instrument, Face Amount			700,000,000.0
Payments of Debt Issuance Costs			$ 3,900,000
Debt Instrument, Interest Rate, Stated Percentage			4.875%
Senior Unsecured 2027 Notes [Member]
Summary of Long-term debt
Debt Instrument, Face Amount			$ 500,000,000.0
Payments of Debt Issuance Costs			$ 2,600,000
Debt Instrument, Frequency of Periodic Payment			semi-annually
Long-term Debt, Gross													500,000,000	0		500,000,000
Debt Instrument, Interest Rate, Stated Percentage			5.50%
Periodic payment of interest			$ 13,800,000
Senior Unsecured 2027 Notes [Member] | Scenario, Forecast [Member]
Summary of Long-term debt
Periodic payment of interest	$ 13,900,000
HWP Refinance Loan [Member]
Summary of Long-term debt
Debt Instrument, Face Amount											$ 33,000,000.0
Debt Instrument, Frequency of Periodic Payment											Monthly
Long-term Debt, Gross													28,867,000	29,161,000		28,867,000
Debt Instrument, Periodic Payment											$ 200,000
Restricted Cash and Cash Equivalents, Current													$ 2,800,000	$ 3,900,000		$ 2,800,000
Debt Instrument, Interest Rate, Stated Percentage											6.72%