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Long-Term Obligations - Senior Notes - Due 2026 - Additional Information (Detail) - 6.625% Senior Notes due 2026 [Member] - Senior Notes [Member]
1 Months Ended 12 Months Ended
Aug. 31, 2018
Dec. 31, 2020
Debt Instrument [Line Items]    
Notes issued rate 6.625% 6.625%
Debt instrument maturity date Aug. 31, 2026 Aug. 01, 2026
Debt instrument, frequency of periodic payment   semi-annually
Repurchase of senior notes of principal amount   101.00%
Debt Instrument Redemption By Equity Offering Before August 1, 2021 [Member]    
Debt Instrument [Line Items]    
Percentage of principal amount redeemed   40.00%
Percentage price of principal amount redeemed   106.625%
Equity offering for senior notes description   cash proceeds from certain equity offerings
Debt Instrument Redemption By Equity Offering Before August 1, 2021 [Member]    
Debt Instrument [Line Items]    
Percentage of principal amount redeemed   100.00%