Reportable Segments and Geographic Information - Segment Reporting Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues	$ 83,357	$ 84,047	$ 249,220	$ 219,949
Cost of sales and other operating costs	69,779	62,083	215,067	181,485
Income from equity method investments	(637)	(3,822)	(1,877)	(11,828)
Interest and financing expense, net	6,898	5,026	19,330	13,976
Project development and startup costs	2,543	6,803	12,101	10,523
Other income		(360)	(879)	(360)
Depreciation, amortization, and accretion	5,566	4,697	16,772	12,677
Other segment items	2,389	1,419	4,767	2,690
Segment income (loss)	(3,181)	8,201	(16,061)	10,786
Income tax benefit	14,567	8,906	36,290	8,906
Net income	11,386	17,107	20,229	19,692
Investment in other entities	227,545		227,545		$ 223,594
Segment assets	916,749		916,749		881,077
Intersegment Eliminations
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues	(5,533)	(4,649)	(15,094)	(15,447)
Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues	83,357	84,047	249,220	219,949
Cost of sales and other operating costs	57,921	51,368	173,602	147,457
Income from equity method investments	(637)	(3,822)	(1,877)	(11,828)
Interest and financing expense, net	6,898	5,026	19,330	13,976
Project development and startup costs	2,543	6,803	12,101	10,523
Other income		(349)	(64)	(349)
Depreciation, amortization, and accretion	5,566	4,697	16,772	12,677
Other segment items	55	(447)	(1,290)	(1,043)
Segment income (loss)	11,011	20,771	30,646	48,536
Investment in other entities	227,545		227,545		223,594
Segment assets	876,135		876,135		845,748
Corporate
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues	0	0	0	0
Cost of sales and other operating costs	11,858	10,715	41,465	34,028
Income from equity method investments	0	0	0	0
Interest and financing expense, net	0	0	0	0
Project development and startup costs	0	0	0	0
Other income		(11)	(815)	(11)
Depreciation, amortization, and accretion	0	0	0	0
Other segment items	2,334	1,866	6,057	3,733
Investment in other entities	0		0		0
Segment assets	40,614		40,614		35,329
Corporate and Eliminations
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues	0	0	0	0
Segment income (loss)	(14,192)	(12,570)	(46,707)	(37,750)
RNG Fuel
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues	22,921	25,864	75,650	63,036
RNG Fuel | Intersegment Eliminations
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues	(139)	(129)	(415)	(388)
RNG Fuel | Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues	22,921	25,864	75,650	63,036
Cost of sales and other operating costs	11,774	9,985	35,341	26,644
Income from equity method investments	(637)	(3,822)	(1,877)	(11,828)
Interest and financing expense, net	6,929	4,958	19,333	13,969
Project development and startup costs	2,543	6,803	12,101	10,523
Other income		0	0	0
Depreciation, amortization, and accretion	3,031	2,124	8,985	5,482
Other segment items	(27)	(300)	(214)	(627)
Segment income (loss)	(692)	6,116	1,981	18,873
Investment in other entities	227,545		227,545		223,594
Segment assets	660,922		660,922		635,927
Fuel Station Services
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues	51,722	45,395	149,426	121,794
Fuel Station Services | Intersegment Eliminations
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues	(5,394)	(4,520)	(14,679)	(15,059)
Fuel Station Services | Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues	51,722	45,395	149,426	121,794
Cost of sales and other operating costs	40,230	33,609	118,683	94,882
Income from equity method investments	0	0	0	0
Interest and financing expense, net	(11)	95	45	119
Project development and startup costs	0	0	0	0
Other income		0	0	0
Depreciation, amortization, and accretion	1,573	1,574	4,924	4,183
Other segment items	81	(145)	(1,076)	(443)
Segment income (loss)	9,849	10,262	26,850	23,053
Investment in other entities	0		0		0
Segment assets	184,555		184,555		179,304
Renewable Power
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues	8,714	12,788	24,144	35,119
Renewable Power | Intersegment Eliminations
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues	0	0	0	0
Renewable Power | Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues	8,714	12,788	24,144	35,119
Cost of sales and other operating costs	5,917	7,774	19,578	25,931
Income from equity method investments	0	0	0	0
Interest and financing expense, net	(20)	(27)	(48)	(112)
Project development and startup costs	0	0	0	0
Other income		(349)	(64)	(349)
Depreciation, amortization, and accretion	962	999	2,863	3,012
Other segment items	1	(2)	0	27
Segment income (loss)	1,854	$ 4,393	1,815	$ 6,610
Investment in other entities	0		0		0
Segment assets	$ 30,658		$ 30,658		$ 30,517