Debt - Schedule of Redemption Price Percentages (Details) - Norwegian Bond Debt	12 Months Ended
	Dec. 31, 2018
First Call Date to, but not including, the Interest Payment Date in November 2020
Debt Instrument, Redemption [Line Items]
Redemption price percentage	104.125%
Interest Payment Date in November 2020 to but not including, the Interest Payment Date in May 2021
Debt Instrument, Redemption [Line Items]
Redemption price percentage	103.30%
Interest Payment Date in May 2021 to, but not including, the Interest Payment Date in November 2021
Debt Instrument, Redemption [Line Items]
Redemption price percentage	102.475%
Interest Payment Date in November 2021 to, but not including, the Interest Payment Date in May 2022
Debt Instrument, Redemption [Line Items]
Redemption price percentage	101.65%
Interest Payment Date in May 2022 to, but not including, the Maturity Date
Debt Instrument, Redemption [Line Items]
Redemption price percentage	100.00%