Earnings per share - Schedule of Earnings Per Share, Basic and Diluted (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2022	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Net loss	$ (3,043)	$ (3,043)
Less net income (loss) attributable to non-controlling interest	(831)	(831)	$ 502	$ (1,647)	$ 1,261
Less net loss attributable to non-controlling interest - ENE Onshore	(831)	(831)	502	(1,647)	1,261
Net loss attributable to shareholders - basic and diluted	$ (2,031)	$ 2,031	0	$ 2,031	0
Weighted average shares outstanding - basic	26,254,167	26,254,167		26,254,167
Issued upon assumed exercise of outstanding stock options	0
Dilutive effect of unvested restricted common stock	0
Class B Common Stock converted to Class A Common Stock	0
Weighted average shares outstanding - diluted	26,254,167	26,254,167		26,254,167
Earnings Per Share, Basic [Abstract]
Basic	$ (0.08)	$ 0.08		$ 0.08
Diluted	$ (0.08)	$ 0.08		$ 0.08
ENE Onshore [Member]
Less net income (loss) attributable to non-controlling interest	$ (181)	$ (181)	(1,941)	$ (418)	(3,936)
Less net loss attributable to non-controlling interest - ENE Onshore	$ (181)	$ (181)	$ (1,941)	$ (418)	$ (3,936)