Revenues from Contracts with Customers and Other Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Disaggregation of Revenue [Line Items]
Total operating revenue	$ 5,260	$ 4,238	$ 9,250	$ 8,298
Renewable Natural Gas Commodity
Disaggregation of Revenue [Line Items]
Total operating revenue	141	140	360	270
Environmental attribute revenue
Disaggregation of Revenue [Line Items]
Total operating revenue	4,182	2,777	7,953	6,310
Licensing and development revenue
Disaggregation of Revenue [Line Items]
Total operating revenue	800	1,300	800	1,300
Other hydrocarbon revenue - ethanol, isooctane, IBA
Disaggregation of Revenue [Line Items]
Total operating revenue	$ 137	$ 21	$ 137	$ 418