BUSINESS SEGMENTS - Summarized Financial Information Concerning Reportable Segments (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2025 USD ($) Segment	Mar. 31, 2024 USD ($)	Dec. 31, 2024 USD ($)
Segment Reporting Information [Line Items]
Net revenue from external customers	$ 229,762	$ 224,166
Depreciation and amortization expenses	69,777	62,351
Gross profit	72,927	78,810
Segment operating income (loss)	50,913	52,583
Segment assets	5,838,947	5,516,844	$ 5,666,224
Expenditures for long-lived assets	$ 192,602	103,386
Number of segment, allocation of other segment items | Segment	2
Goodwill	$ 151,291		$ 151,023
Electricity
Segment Reporting Information [Line Items]
Depreciation and amortization expenses	59,976	55,049
Expenditures for long-lived assets	171,350	92,163
Goodwill	146,700	146,500
Electricity | Accounted for Under ASC 606
Segment Reporting Information [Line Items]
Net revenue from external customers	40,200	44,800
Product
Segment Reporting Information [Line Items]
Depreciation and amortization expenses	2,894	2,873
Expenditures for long-lived assets	1,200	1,322
Goodwill	0	0
Energy Storage
Segment Reporting Information [Line Items]
Depreciation and amortization expenses	6,908	4,429
Expenditures for long-lived assets	20,052	9,901
Goodwill	4,600	4,600
Energy Storage | Accounted for Under ASC 606
Segment Reporting Information [Line Items]
Net revenue from external customers	3,500	700
United States
Segment Reporting Information [Line Items]
Net revenue from external customers	155,204	152,773
Foreign
Segment Reporting Information [Line Items]
Net revenue from external customers	74,558	71,393
Operating Segments
Segment Reporting Information [Line Items]
Depreciation and amortization expenses	66,293	59,203
Other cost of revenues expenses	90,542	86,153
Gross profit	72,927	78,810
Segment operating expenses (income)	22,014	26,227
Segment operating income (loss)	50,913	52,583
Operating Segments | Electricity
Segment Reporting Information [Line Items]
Net revenue from external customers	180,241	191,253
Depreciation and amortization expenses	56,870	52,189
Other cost of revenues expenses	62,963	64,541
Gross profit	60,408	74,523
Segment operating expenses (income)	19,565	21,842
Segment operating income (loss)	40,843	52,681
Segment assets	5,124,073	4,961,483
Operating Segments | Product
Segment Reporting Information [Line Items]
Net revenue from external customers	31,769	24,832
Depreciation and amortization expenses	2,571	2,563
Other cost of revenues expenses	22,113	18,591
Gross profit	7,085	3,678
Segment operating expenses (income)	3,449	2,836
Segment operating income (loss)	3,636	842
Segment assets	244,796	190,210
Operating Segments | Energy Storage
Segment Reporting Information [Line Items]
Net revenue from external customers	17,752	8,081
Depreciation and amortization expenses	6,851	4,451
Other cost of revenues expenses	5,467	3,021
Gross profit	5,434	609
Segment operating expenses (income)	(1,000)	1,549
Segment operating income (loss)	6,434	(940)
Segment assets	470,078	365,151
Operating Segments | United States | Electricity
Segment Reporting Information [Line Items]
Net revenue from external customers	134,213	143,816
Operating Segments | United States | Product
Segment Reporting Information [Line Items]
Net revenue from external customers	3,239	876
Operating Segments | United States | Energy Storage
Segment Reporting Information [Line Items]
Net revenue from external customers	17,752	8,081
Operating Segments | Foreign | Electricity
Segment Reporting Information [Line Items]
Net revenue from external customers	46,028	47,437
Operating Segments | Foreign | Product
Segment Reporting Information [Line Items]
Net revenue from external customers	28,530	23,956
Operating Segments | Foreign | Energy Storage
Segment Reporting Information [Line Items]
Net revenue from external customers	0	0
Segment Reconciling Items
Segment Reporting Information [Line Items]
Segment assets	158,618	127,386
Segment Reconciling Items | Electricity
Segment Reporting Information [Line Items]
Segment assets	158,618	127,386
Segment Reconciling Items | Product
Segment Reporting Information [Line Items]
Segment assets	0	0
Segment Reconciling Items | Energy Storage
Segment Reporting Information [Line Items]
Segment assets	$ 0	$ 0