Revenue - Estimated future revenue (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($)
Revenue
Total estimated future revenue	$ 682,418
Sales of fuel cell systems
Revenue
Total estimated future revenue	23,142
Sale of hydrogen installations and other infrastructure
Revenue
Total estimated future revenue	36,243
Sale of electrolyzers
Revenue
Total estimated future revenue	49,158
Sale of oil and gas equipment
Revenue
Total estimated future revenue	91,586
Services performed on fuel cell systems and related infrastructure
Revenue
Total estimated future revenue	102,362
Power Purchase Agreements
Revenue
Total estimated future revenue	249,063
Fuel delivered to customers
Revenue
Total estimated future revenue	61,602
Sale of cryogenic equipment
Revenue
Total estimated future revenue	46,513
Other
Revenue
Total estimated future revenue	$ 22,749
Maximum | Sales of fuel cell systems
Revenue
Duration of estimated revenue expected to be recognized in future (in years)	1 year
Maximum | Sale of hydrogen installations and other infrastructure
Revenue
Duration of estimated revenue expected to be recognized in future (in years)	1 year
Maximum | Services performed on fuel cell systems and related infrastructure
Revenue
Duration of estimated revenue expected to be recognized in future (in years)	7 years
Maximum | Power Purchase Agreements
Revenue
Duration of estimated revenue expected to be recognized in future (in years)	7 years
Minimum | Services performed on fuel cell systems and related infrastructure
Revenue
Duration of estimated revenue expected to be recognized in future (in years)	5 years
Minimum | Power Purchase Agreements
Revenue
Duration of estimated revenue expected to be recognized in future (in years)	5 years