Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 27, 2020	Dec. 31, 2019
Trade accounts and notes receivable, allowance for doubtful accounts	$ 3,066	$ 1,145
Property, plant and equipment, accumulated depreciation	558,433	522,424
Intangible assets, Accumulated amortization	437,450	409,328
Unamortized discount and debt issuance costs	$ 11,008	$ 9,516
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	400,000,000	400,000,000
Common stock, shares issued	134,948,625	134,929,768
Common stock, shares outstanding	134,746,225	134,727,368
Treasury stock, shares outstanding	202,400	202,400