Debt Redemption Price Schedule (Details) - Subsequent Event - Senior Notes - Senior Notes Due 2026	Oct. 04, 2018
2021
Debt Instrument, Redemption [Line Items]
Redemption price, percentage	104.406%
2022
Debt Instrument, Redemption [Line Items]
Redemption price, percentage	102.938%
2023
Debt Instrument, Redemption [Line Items]
Redemption price, percentage	101.469%
2024 and thereafter
Debt Instrument, Redemption [Line Items]
Redemption price, percentage	100.00%