Long-Term Debt - Redemption Price, Percentage (Detail)	12 Months Ended
	Dec. 31, 2016
7.0% Senior Subordinated Notes Due 2022 [Member] | Beginning on July 15, 2017 [Member]
Debt Instrument Redemption [Line Items]
Redemption Price	103.50%
7.0% Senior Subordinated Notes Due 2022 [Member] | Beginning on July 15, 2018 [Member]
Debt Instrument Redemption [Line Items]
Redemption Price	102.333%
7.0% Senior Subordinated Notes Due 2022 [Member] | Beginning on July 15, 2019 [Member]
Debt Instrument Redemption [Line Items]
Redemption Price	101.167%
7.0% Senior Subordinated Notes Due 2022 [Member] | Beginning on July 15, 2020 and Thereafter [Member]
Debt Instrument Redemption [Line Items]
Redemption Price	100.00%
5.0% Senior Subordinated Notes due 2023 [Member] | Beginning on May 15, 2018 [Member]
Debt Instrument Redemption [Line Items]
Redemption Price	102.50%
5.0% Senior Subordinated Notes due 2023 [Member] | Beginning on May 15, 2019 [Member]
Debt Instrument Redemption [Line Items]
Redemption Price	101.667%
5.0% Senior Subordinated Notes due 2023 [Member] | Beginning on May 15, 2020 [Member]
Debt Instrument Redemption [Line Items]
Redemption Price	100.833%
5.0% Senior Subordinated Notes due 2023 [Member] | Beginning on May 15, 2021 and Thereafter [Member]
Debt Instrument Redemption [Line Items]
Redemption Price	100.00%