Debt - Schedule of the Company's Debt (Detail) - USD ($)		Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015	Mar. 20, 2014
Debt Instrument [Line Items]
Borrowings under the credit facility		$ 185,000,000	$ 0
Other	[1]	8,500,000		$ 13,300,000
Unamortized debt issuance costs		(16,500,000)		(24,300,000)
Total debt		2,387,400,000		2,418,700,000
Less: current portion		(8,200,000)		(231,900,000)
Long-term debt		2,379,200,000		2,186,800,000
8.60% Senior Notes Due August 15, 2016
Debt Instrument [Line Items]
Senior notes				219,600,000
11.25% Senior Notes Due February 1, 2019
Debt Instrument [Line Items]
Senior notes	[2]	172,200,000		172,200,000
7.625% Senior Notes Due June 15, 2020
Debt Instrument [Line Items]
Senior notes		350,000,000		350,000,000
7.875% Senior Notes Due March 15, 2021
Debt Instrument [Line Items]
Senior notes		448,800,000		448,500,000
8.875% Debentures Due April 15, 2021
Debt Instrument [Line Items]
Debentures		80,900,000		80,900,000
7.00% Senior Notes Due February 15, 2022
Debt Instrument [Line Items]
Senior notes		140,000,000		140,000,000
6.50% Senior Notes Due November 15, 2023
Debt Instrument [Line Items]
Senior notes		350,000,000		350,000,000
6.00% Senior Notes Due April 1, 2024
Debt Instrument [Line Items]
Senior notes		400,000,000		400,000,000	$ 400,000,000
6.625% Debentures Due April 15, 2029
Debt Instrument [Line Items]
Debentures		199,500,000		199,500,000
8.820% Debentures Due April 15, 2031
Debt Instrument [Line Items]
Debentures		$ 69,000,000		$ 69,000,000

[1] Includes miscellaneous debt obligations and capital leases.

[2] As of December 31, 2015, the interest rate on the 11.25% senior notes due February 1, 2019 was 12.75% as a result of downgrades in the ratings of the notes by the rating agencies. As a result of a ratings downgrade on February 2, 2016, the interest rate increased from 12.75% to 13.0% in February 2016. As a result of a ratings downgrade on October 6, 2016, the rate increased to 13.25%. The maximum interest rate on these notes is 13.25%.