Segment Information - Revenue and Gross Profit (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2024	Oct. 01, 2023	Sep. 29, 2024	Oct. 01, 2023
Segment Reporting Information [Line Items]
Consolidated revenue	$ 720,053	$ 774,889	$ 1,920,151	$ 2,233,961
Consolidated gross profit	75,793	87,613	149,576	219,534
Operating Segments | U.S. Gas
Segment Reporting Information [Line Items]
Consolidated revenue	366,070	395,745	933,334	1,046,964
Consolidated gross profit	27,960	52,103	49,140	99,509
Operating Segments | Canadian Gas
Segment Reporting Information [Line Items]
Consolidated revenue	50,354	54,590	125,992	141,977
Consolidated gross profit	11,789	10,020	26,692	22,070
Operating Segments | Union Electric
Segment Reporting Information [Line Items]
Consolidated revenue	171,666	204,135	499,728	628,029
Consolidated gross profit	15,427	11,724	38,875	44,030
Operating Segments | Non-Union Electric
Segment Reporting Information [Line Items]
Consolidated revenue	128,844	110,715	345,971	380,882
Consolidated gross profit	21,437	12,802	40,474	51,864
Other
Segment Reporting Information [Line Items]
Consolidated revenue	3,119	9,704	15,126	36,109
Consolidated gross profit	$ (820)	$ 964	$ (5,605)	$ 2,061