Long-term debt - Related party - Schedule of Long Term Related Party weighted average interest rate (Details)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
KFMC Note
Debt Instrument [Line Items]
Debt instrument weighted average interest rate	1.90%	1.60%	2.90%
KFMC Note | Minimum
Debt Instrument [Line Items]
Debt instrument interest rate	1.60%	1.60%	1.70%
KFMC Note | Maximum
Debt Instrument [Line Items]
Debt instrument interest rate	2.00%	1.60%	3.30%
KFMC-ENE Onshore Note
Debt Instrument [Line Items]
Debt instrument weighted average interest rate	3.30%	1.60%	2.20%
KFMC-ENE Onshore Note | Minimum
Debt Instrument [Line Items]
Debt instrument interest rate	1.60%	1.60%	1.60%
KFMC-ENE Onshore Note | Maximum
Debt Instrument [Line Items]
Debt instrument interest rate	5.10%	1.70%	3.30%