The end date of the period reflected on the cover page if a periodic report. For all other reports and registration statements containing historical data, it is the date up through which that historical data is presented. If there is no historical data in the report, use the filing date. The format of the date is CCYY-MM-DD.

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Debt (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Debt (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Debt Instrument [Line Items]
Document Period End Date		Jun. 30, 2019
Repayments of Debt		$ 836,800	$ 268,200
Term Loan	$ 700,000	700,000
Bank Credit Facility	0	0		$ 387,061
Letters of Credit Outstanding, Amount	32,900	32,900
Line of Credit Facility, Increase (Decrease), Net		55,000
Unamortized debt issuance costs	(39,428)	(39,428)		(31,762)
Total debt	3,631,986	3,631,986		3,602,078
Less: Current maturities of long-term debt	(167,084)	(167,084)		(69,896)
Total long-term debt	3,464,902	3,464,902		3,532,182
October 2018
Debt Instrument [Line Items]
Line of Credit Facility, Increase (Decrease), Net			$ 370,000
January 2022
Debt Instrument [Line Items]
Repayments of Debt		326,100
April 2027
Debt Instrument [Line Items]
Repayments of Debt		15,700
December 2022
Debt Instrument [Line Items]
Term Loan	650,000	650,000		0
Bank Credit Facility	0	0
Letters of Credit Outstanding, Amount				395,000
Term Loan [Member]
Debt Instrument [Line Items]
Repayments of Debt	32,100	40,500
Line of Credit Facility, Increase (Decrease), Net	17,200
June 2029 [Member]
Debt Instrument [Line Items]
Unamortized debt issuance costs	(15,500)	(15,500)
Term Loan 2022 [Member]
Debt Instrument [Line Items]
Senior Notes	0	0		641,250
Unsecured Debt
Debt Instrument [Line Items]
Unamortized pricing discounts and other	6,103	6,103		6,562
Unsecured Debt \| November 2020
Debt Instrument [Line Items]
Senior Notes	200,000	200,000		200,000
Unsecured Debt \| November 2021
Debt Instrument [Line Items]
Senior Notes	150,000	150,000		150,000
Unsecured Debt \| January 2022
Debt Instrument [Line Items]
Senior Notes	98,906	98,906		425,000
Unsecured Debt \| May 2024
Debt Instrument [Line Items]
Senior Notes	850,000	850,000		850,000
Unsecured Debt \| April 2027
Debt Instrument [Line Items]
Senior Notes	184,350	184,350		200,000
Unsecured Debt \| December 2027
Debt Instrument [Line Items]
Senior Notes	550,000	550,000		550,000
Unsecured Debt \| June 2029 [Member]
Debt Instrument [Line Items]
Senior Notes	750,000	750,000		0
Capital Lease Obligations
Debt Instrument [Line Items]
Obligations under capital leases	197,230	197,230		211,952
Mortgages [Member]
Debt Instrument [Line Items]
Mortgage notes and other debt	$ 34,825	$ 34,825		$ 4,076