Long-Term Obligations - Summary of Debt Instrument Redemption (Detail) - 6.625% Senior Notes due 2026 [Member] - Senior Notes [Member]	12 Months Ended
	Dec. 31, 2020
Twelve-Month Period Beginning on August 1, 2021 [Member]
Debt Instrument Redemption [Line Items]
Percentage of principal amount to be redeemed	103.313%
Twelve-Month Period Beginning on August 1, 2022 [Member]
Debt Instrument Redemption [Line Items]
Percentage of principal amount to be redeemed	101.656%
Twelve-Month Period Beginning on August 1, 2023 and Thereafter [Member]
Debt Instrument Redemption [Line Items]
Percentage of principal amount to be redeemed	100.00%