RESTRUCTURING ACTIVITIES - Summary of Restructuring Activity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Restructuring Cost and Reserve [Line Items]
Restructuring activities	$ 560	$ 4,869	$ 11,849
Cumulative costs to date	45,743
Severance and related costs
Restructuring Cost and Reserve [Line Items]
Restructuring activities	(353)	4,039	6,740
Cumulative costs to date	36,898
Other
Restructuring Cost and Reserve [Line Items]
Restructuring activities	913	830	5,109
Cumulative costs to date	8,845
Operating Segments | B&W Renewable segment
Restructuring Cost and Reserve [Line Items]
Restructuring activities	900	1,876	5,926
Operating Segments | B&W Renewable segment | Severance and related costs
Restructuring Cost and Reserve [Line Items]
Restructuring activities	719	1,732	4,537
Operating Segments | B&W Renewable segment | Other
Restructuring Cost and Reserve [Line Items]
Restructuring activities	181	144	1,389
Operating Segments | B&W Environmental segment
Restructuring Cost and Reserve [Line Items]
Restructuring activities	228	430	745
Operating Segments | B&W Environmental segment | Severance and related costs
Restructuring Cost and Reserve [Line Items]
Restructuring activities	28	360	293
Operating Segments | B&W Environmental segment | Other
Restructuring Cost and Reserve [Line Items]
Restructuring activities	200	70	452
Operating Segments | B&W Thermal segment
Restructuring Cost and Reserve [Line Items]
Restructuring activities	589	2,207	4,725
Operating Segments | B&W Thermal segment | Severance and related costs
Restructuring Cost and Reserve [Line Items]
Restructuring activities	128	1,734	1,962
Operating Segments | B&W Thermal segment | Other
Restructuring Cost and Reserve [Line Items]
Restructuring activities	461	473	2,763
Corporate
Restructuring Cost and Reserve [Line Items]
Restructuring activities	(1,157)	356	453
Corporate | Severance and related costs
Restructuring Cost and Reserve [Line Items]
Restructuring activities	(1,228)	213	(52)
Corporate | Other
Restructuring Cost and Reserve [Line Items]
Restructuring activities	$ 71	$ 143	$ 505