Financial instruments - Financial Assets and Financial Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Assets
Investment in equity securities	$ 20,467	$ 17,806
Interest rate swap
Assets
Derivative asset		11,650
Commodity swap
Assets
Derivative asset		104,797
Contingent consideration derivative liabilities
Contingent consideration derivative liabilities	2,816
Contingent consideration derivative liabilities
Contingent consideration derivative liabilities
Contingent consideration derivative liabilities	44,552	46,619
Level 1
Assets
Investment in equity securities	12,789	10,128
Level 1 | Interest rate swap
Assets
Derivative asset		0
Level 1 | Commodity swap
Assets
Derivative asset		0
Contingent consideration derivative liabilities
Contingent consideration derivative liabilities	0
Level 1 | Contingent consideration derivative liabilities
Contingent consideration derivative liabilities
Contingent consideration derivative liabilities	0	0
Level 2
Assets
Investment in equity securities	0	0
Level 2 | Interest rate swap
Assets
Derivative asset		11,650
Level 2 | Commodity swap
Assets
Derivative asset		104,797
Contingent consideration derivative liabilities
Contingent consideration derivative liabilities	2,816
Level 2 | Contingent consideration derivative liabilities
Contingent consideration derivative liabilities
Contingent consideration derivative liabilities	0	0
Level 3
Assets
Investment in equity securities	7,678	7,678
Level 3 | Interest rate swap
Assets
Derivative asset		0
Level 3 | Commodity swap
Assets
Derivative asset		0
Contingent consideration derivative liabilities
Contingent consideration derivative liabilities	0
Level 3 | Contingent consideration derivative liabilities
Contingent consideration derivative liabilities
Contingent consideration derivative liabilities	$ 44,552	$ 46,619