Earnings Per Unit (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 25, 2022	Jun. 26, 2021	Jun. 25, 2022	Jun. 26, 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)	$ 5,071	$ 10,233	$ 11,176	$ 13,746
Weighted average outstanding units (denominator)	735,385	735,385	735,385	735,385
Per unit amount	$ 6.90	$ 13.92	$ 15.20	$ 18.69
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)	$ 45,643	$ 92,101	$ 100,585	$ 123,717
Weighted average outstanding units (denominator)	755,385	755,385	755,385	755,385
Per unit amount	$ 60.42	$ 121.93	$ 133.16	$ 163.78