INVENTORTIES (Details) - USD ($) $ in Thousands	Apr. 01, 2018	Dec. 31, 2017
Inventory [Line Items]
Raw materials	$ 113,756	$ 96,846
Work in process	13,210	10,720
Finished goods	33,650	22,936
Total manufactured goods, net	156,835	127,415
Materials purchased for resale (distribution products)	51,079	49,392
Total materials purchased for resale (distribution products), net	49,067	47,855
Total inventories	205,902	175,270
Manufactured Goods [Member]
Inventory [Line Items]
Less: reserve for inventory obsolescence	(3,781)	(3,087)
Distributed Goods [Member]
Inventory [Line Items]
Less: reserve for inventory obsolescence	$ (2,012)	$ (1,537)