Segment Information - Depreciation by Segment (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 29, 2026	Mar. 30, 2025
Segment Reporting Information [Line Items]
Consolidated depreciation expense	$ 27,359	$ 27,557
Cost of Sales
Segment Reporting Information [Line Items]
Consolidated depreciation expense	26,970	27,185
Operating Segments \| Cost of Sales \| U.S. Gas
Segment Reporting Information [Line Items]
Consolidated depreciation expense	9,979	11,157
Operating Segments \| Cost of Sales \| Canadian Operations
Segment Reporting Information [Line Items]
Consolidated depreciation expense	1,692	1,432
Operating Segments \| Cost of Sales \| Union Electric
Segment Reporting Information [Line Items]
Consolidated depreciation expense	7,380	7,278
Operating Segments \| Cost of Sales \| Non-Union Electric
Segment Reporting Information [Line Items]
Consolidated depreciation expense	$ 7,919	$ 7,318

The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration