Segment Information - Schedule of Reconciliation to Consolidated Amounts (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Segment Reporting Information [Line Items]
Depreciation and Amortization	$ 29,979	$ 29,375
Interest Expense	12,636	11,553
Income Tax Expense (Benefit)	4,876	10,085
Net Income	72,610	68,099
Operating Segments
Segment Reporting Information [Line Items]
Interest Expense	12,481	11,426
Income Tax Expense (Benefit)	7,684	11,557
Net Income	72,473	69,679
Operating Segments \| Electric
Segment Reporting Information [Line Items]
Depreciation and Amortization	23,445	22,377
Interest Expense	11,736	10,657
Income Tax Expense (Benefit)	(5,182)	(4,008)
Net Income	35,250	24,708
Operating Segments \| Manufacturing
Segment Reporting Information [Line Items]
Depreciation and Amortization	4,787	5,424
Interest Expense	599	623
Income Tax Expense (Benefit)	1,247	272
Net Income	4,283	1,532
Operating Segments \| Plastics
Segment Reporting Information [Line Items]
Depreciation and Amortization	1,672	1,546
Interest Expense	146	146
Income Tax Expense (Benefit)	11,619	15,293
Net Income	32,940	43,439
Corporate
Segment Reporting Information [Line Items]
Depreciation and Amortization	75	28
Interest Expense	155	127
Income Tax Expense (Benefit)	(2,808)	(1,472)
Net Income	$ 137	$ (1,580)