Earnings Per Unit (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 24, 2022	Sep. 25, 2021	Sep. 24, 2022	Sep. 25, 2021
Class A Units [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Income attributable to USPB available to unitholders (numerator)	$ 4,312	$ 12,102	$ 15,489	$ 25,848
Weighted average outstanding units (denominator)	735,385	735,385	735,385	735,385
Per unit amount	$ 5.86	$ 16.46	$ 21.06	$ 35.15
Class B Units [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Income attributable to USPB available to unitholders (numerator)	$ 38,812	$ 108,918	$ 139,397	$ 232,635
Weighted average outstanding units (denominator)	755,385	755,385	755,385	755,385
Per unit amount	$ 51.38	$ 144.19	$ 184.54	$ 307.97