Long-Term Indebtedness (Details) - USD ($)										3 Months Ended		6 Months Ended
	Jan. 15, 2021	Jan. 31, 2017	Jun. 30, 2016	Jun. 16, 2016	Dec. 23, 2013	Jul. 15, 2013	Dec. 21, 2012	Dec. 20, 2011	Nov. 05, 2007	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015	Apr. 30, 2014
Summary of Long-term debt
Existing Cash Used To Retire Long-Term Debt								$ 15,000,000
Loss on debt extinguishment										$ (2,377,000)	$ (6,557,000)	$ (2,377,000)	$ (6,557,000)
Payments of Debt Issuance Costs												5,229,000	9,993,000
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
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, Description of Variable Rate Basis								LIBOR
Interest rate, variable interest rate floor (as a percent)								1.00%
Debt Instrument, Interest Rate, Effective Percentage														3.50%
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%
Debt Instrument, Description of Variable Rate Basis					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 2016 [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 [Member]
Summary of Long-term debt
Debt Instrument, Basis Spread on Variable Rate				2.50%
Debt Instrument, Description of Variable Rate Basis				LIBOR
Payments of Debt Issuance Costs				$ 1,000,000
Amended and Restated Revolving Loan [Member]
Summary of Long-term debt
Line of Credit Facility, Maximum Borrowing Capacity											250,000,000.0		$ 250,000,000.0
Debt Instrument, Description of Variable Rate Basis			LIBOR
Long-term Line of Credit			$ 0							0		0		$ 0
Letters of Credit Outstanding, Amount			$ 19,700,000							19,700,000		$ 19,700,000		20,100,000
Debt Instrument, Frequency of Periodic Payment			annual
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage												0.375%	0.375%
Amended and Restated Term Loan B [Member]
Summary of Long-term debt
Debt Instrument, Face Amount											$ 700,000,000.0		$ 700,000,000.0
Line of Credit Facility, Additional Contingent Borrowing Capacity			$ 350,000,000.0							350,000,000.0		$ 350,000,000.0
Debt Instrument, Description of Variable Rate Basis			LIBOR
Interest rate, variable interest rate floor (as a percent)			0.75%
Debt Instrument, Frequency of Periodic Payment			annual		quarterly
Long-term Debt, Gross			$ 544,750,000							$ 544,750,000		$ 544,750,000		696,500,000
Debt Instrument, Interest Rate, Effective Percentage			3.25%							3.25%		3.25%
Debt Instrument, Periodic Payment												$ 1,800,000
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
Debt Instrument, Frequency of Periodic Payment							semi-annual
Long-term Debt, Gross			$ 800,000,000							$ 800,000,000		800,000,000		800,000,000
Debt Instrument, Interest Rate, Stated Percentage							5.25%
Periodic payment of interest						$ 22,300,000	$ 21,000,000
Senior Unsecured 2021 Notes [Member] | Scenario, Forecast [Member]
Summary of Long-term debt
Periodic payment of interest	$ 21,000,000
Senior Unsecured 2024 Notes [Member]
Summary of Long-term debt
Debt Instrument, Face Amount				300,000,000.0
Extinguishment of Debt, Amount				150,000,000
Payments of Debt Issuance Costs				$ 4,700,000
Debt Instrument, Frequency of Periodic Payment				semi-annually
Long-term Debt, Gross			300,000,000							300,000,000		300,000,000		0
Debt Instrument, Interest Rate, Stated Percentage				4.875%
Periodic payment of interest				$ 7,300,000
Senior Unsecured 2024 Notes [Member] | Scenario, Forecast [Member]
Summary of Long-term debt
Periodic payment of interest		$ 9,100,000
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			29,391,000							29,391,000		29,391,000		29,667,000
Debt Instrument, Periodic Payment									$ 200,000
Debt Instrument, Interest Rate, Stated Percentage									6.72%
Amounts Deposited Into Escrow			$ 3,500,000							$ 3,500,000		$ 3,500,000		$ 3,000,000
Old Debt - First Lien Amendment [Member]
Summary of Long-term debt
Extinguishment of Debt, Amount								$ 950,000,000