Inventory (Details) - USD ($) $ in Thousands	Sep. 12, 2015	Jan. 03, 2015
Inventory Disclosure [Abstract]
Used oil and processed oil	$ 10,757	$ 14,153
Solvents and solutions	6,734	8,859
Machines	4,539	3,659
Drums and supplies	3,628	2,756
Other	1,745	1,617
Total inventory	27,403	31,044
Less: machine refurbishing reserve	(288)	(246)
Total inventory - net	$ 27,115	$ 30,798