Debt and Other Obligations (Textuals) (Details)	12 Months Ended
	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Debt Instrument [Line Items]
Total debt and other obligations	$ 995,431,000				$ 994,047,000
Face value of debt	995,431,000	$ 995,085,000	$ 994,739,000	$ 994,393,000	994,047,000	$ 993,701,000	$ 993,355,000	$ 993,009,000
2012 Secured Notes [Member]
Debt Instrument [Line Items]
Face value of debt	995,400,000				$ 994,000,000.0
High Yield Bonds [Member] | 2012 Secured Notes [Member]
Debt Instrument [Line Items]
Debt covenant, trade payable restriction of equipment, land or other property, amount	$ 100,000,000.0
Debt covenant, debt to adjusted consolidated cash flow	3.5
Debt to adjusted cash flow ratio	2.3
Previously outstanding 2012 secured notes tranche A [Member] | 2012 Secured Notes [Member]
Debt Instrument [Line Items]
Total debt and other obligations									$ 500,000,000.0
Stated interest rate									2.381%
2012 secured notes tranche B [Member] | 2012 Secured Notes [Member]
Debt Instrument [Line Items]
Total debt and other obligations	$ 1,000,000,000.0
Stated interest rate	3.849%