Transactions with Affiliates - Schedule of Amounts Charged to UTSI (Detail) - Affiliates [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 01, 2016	Sep. 26, 2015	Oct. 01, 2016	Sep. 26, 2015
Related Party Transaction [Line Items]
Cost incurred for services provided by CenTra and affiliates	$ 17,885	$ 18,634	$ 51,260	$ 51,618
Administrative support services [Member]
Related Party Transaction [Line Items]
Cost incurred for services provided by CenTra and affiliates	548	881	1,906	2,374
Truck fuel, tolls and maintenance [Member]
Related Party Transaction [Line Items]
Cost incurred for services provided by CenTra and affiliates	619	1,012	1,864	1,622
Real estate rent and related costs [Member]
Related Party Transaction [Line Items]
Cost incurred for services provided by CenTra and affiliates	4,218	3,149	12,458	9,578
Insurance and employee benefit plans [Member]
Related Party Transaction [Line Items]
Cost incurred for services provided by CenTra and affiliates	12,496	13,374	34,802	37,358
Contracted transportation services [Member]
Related Party Transaction [Line Items]
Cost incurred for services provided by CenTra and affiliates	$ 4	$ 218	$ 230	$ 686