CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Jul. 01, 2017	Dec. 31, 2016
Accounts receivable, reserve for doubtful accounts	$ 9,175	$ 9,091
Property, plant and equipment, accumulated depreciation	$ 85,836	$ 82,998
Preferred stock, par value (in usd per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	2,000,000	2,000,000
Preferred stock, shares issued
Common stock, par value (in usd per share)	$ 0.01	$ 0.01
Common stock, shares authorized	95,000,000	95,000,000
Common stock, shares issued	62,189,296	62,088,592
Treasury stock, shares	4,862,264	4,816,912