Long-term Debt and Lease Obligations - Redemption Percentages for Future Periods (Details) - Senior secured notes [Member]	Dec. 15, 2019	May 15, 2015
Senior Secured Second-Priority Notes Due 2018 (Third Lien Notes) [Member] | Year one [Member]
Debt Instrument, Redemption [Line Items]
Notes redemption percentages		104.0625%
Senior Secured Second-Priority Notes Due 2018 (Third Lien Notes) [Member] | Year two [Member]
Debt Instrument, Redemption [Line Items]
Notes redemption percentages		102.03125%
Senior Secured Second-Priority Notes Due 2018 (Third Lien Notes) [Member] | Year three and thereafter [Member]
Debt Instrument, Redemption [Line Items]
Notes redemption percentages		100.00%
Senior Secured Second Priority Notes Due 2021 (Second Lien Notes) [Member] | Year one [Member] | Forecast [Member]
Debt Instrument, Redemption [Line Items]
Notes redemption percentages	105.50%
Senior Secured Second Priority Notes Due 2021 (Second Lien Notes) [Member] | Year two [Member] | Forecast [Member]
Debt Instrument, Redemption [Line Items]
Notes redemption percentages	103.50%
Senior Secured Second Priority Notes Due 2021 (Second Lien Notes) [Member] | Year three and thereafter [Member] | Forecast [Member]
Debt Instrument, Redemption [Line Items]
Notes redemption percentages	100.00%