Condensed Consolidating Financial Information - Narrative (Details)	Mar. 31, 2018
Debt Instrument [Line Items]
Percentage of subsidiary owned	100.00%
Senior Notes | 6.00% Senior Notes, due 2026
Debt Instrument [Line Items]
Notes bear interest at a rate	6.00%
Senior Notes | Senior Notes Due 2023
Debt Instrument [Line Items]
Notes bear interest at a rate	5.125%
Senior Notes | 5.875% Senior Notes due 2024
Debt Instrument [Line Items]
Notes bear interest at a rate	5.875%
Senior Notes | 5.875% Senior Notes due 2022
Debt Instrument [Line Items]
Notes bear interest at a rate	5.875%