SEGMENT REPORTING - Schedule of Operating Results by Segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Segment Reporting Information [Line Items]
Revenues	$ 257,247	$ 204,049
Eliminations
Segment Reporting Information [Line Items]
Revenues	(1,541)	(1,099)
B&W Renewable segment | Operating Segments
Segment Reporting Information [Line Items]
Revenues	100,112	67,961
B&W Renewable segment | B&W Renewable | Operating Segments
Segment Reporting Information [Line Items]
Revenues	49,132	19,711
B&W Renewable segment | B&W Renewable Services | Operating Segments
Segment Reporting Information [Line Items]
Revenues	16,310	8,288
B&W Renewable segment | Vølund | Operating Segments
Segment Reporting Information [Line Items]
Revenues	18,681	16,336
B&W Renewable segment | B&W Solar | Operating Segments
Segment Reporting Information [Line Items]
Revenues	15,989	23,626
B&W Environmental segment | Operating Segments
Segment Reporting Information [Line Items]
Revenues	39,440	34,948
B&W Environmental segment | B&W Environmental | Operating Segments
Segment Reporting Information [Line Items]
Revenues	20,361	18,185
B&W Environmental segment | SPIG | Operating Segments
Segment Reporting Information [Line Items]
Revenues	16,605	12,060
B&W Environmental segment | GMAB | Operating Segments
Segment Reporting Information [Line Items]
Revenues	2,474	4,703
B&W Thermal segment | Operating Segments
Segment Reporting Information [Line Items]
Revenues	119,236	102,239
B&W Thermal segment | B&W Thermal | Operating Segments
Segment Reporting Information [Line Items]
Revenues	$ 119,236	$ 102,239