Long-Term Debt and Other Borrowing Arrangements - Carrying Values of Long-Term Debt and Other Borrowing Arrangements (Details) - USD ($)	Dec. 31, 2017	Sep. 30, 2017	Jul. 31, 2017	Dec. 31, 2016	Oct. 31, 2016
Debt Instrument [Line Items]
Less unamortized debt issuance costs	$ (23,484,000)			$ (23,287,000)
Long-term debt	1,560,748,000			1,620,161,000
Revolving Credit Facility Mature Two Thousand Twenty Two [Member]
Debt Instrument [Line Items]
Revolving credit agreement due 2022	$ 0			$ 0
3.375% Senior Subordinated Notes Due 2027 [Member]
Debt Instrument [Line Items]
Senior subordinated notes interest rate	3.375%			3.375%
Total senior subordinated notes	$ 540,810,000			$ 0
4.125% Senior Subordinated Notes Due 2026 [Member]
Debt Instrument [Line Items]
Senior subordinated notes interest rate	4.125%			4.125%	4.125%
Total senior subordinated notes	$ 240,360,000			$ 209,081,000
2.875% Senior Subordinated Notes Due 2025 [Member]
Debt Instrument [Line Items]
Senior subordinated notes interest rate	2.875%			2.875%
Total senior subordinated notes	$ 360,540,000			$ 0
5.25% Senior Subordinated Notes Due 2024 [Member]
Debt Instrument [Line Items]
Senior subordinated notes interest rate	5.25%			5.25%
Total senior subordinated notes	$ 200,000,000			$ 200,000,000
5.50% Senior subordinated notes due 2023 [Member]
Debt Instrument [Line Items]
Senior subordinated notes interest rate	5.50%			5.50%
Total senior subordinated notes	$ 242,522,000			$ 529,146,000
5.50% Senior subordinated notes due 2022 [Member]
Debt Instrument [Line Items]
Senior subordinated notes interest rate	5.50%			5.50%
Total senior subordinated notes	$ 0			$ 700,000,000
9.25% Senior Subordinated Notes Due 2019 [Member]
Debt Instrument [Line Items]
Senior subordinated notes interest rate	9.25%			9.25%
Total senior subordinated notes	$ 0			$ 5,221,000
Senior Subordinated Notes [Member]
Debt Instrument [Line Items]
Total senior subordinated notes	$ 1,584,232,000			$ 1,643,448,000
Senior Subordinated Notes [Member] | 3.375% Senior Subordinated Notes Due 2027 [Member]
Debt Instrument [Line Items]
Senior subordinated notes interest rate			3.375%
Senior Subordinated Notes [Member] | 2.875% Senior Subordinated Notes Due 2025 [Member]
Debt Instrument [Line Items]
Senior subordinated notes interest rate		2.875%
Senior Subordinated Notes [Member] | 5.25% Senior Subordinated Notes Due 2024 [Member]
Debt Instrument [Line Items]
Senior subordinated notes interest rate	5.25%
Senior Subordinated Notes [Member] | 5.50% Senior subordinated notes due 2023 [Member]
Debt Instrument [Line Items]
Senior subordinated notes interest rate	5.50%