Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 31, 2019
Trade accounts and notes receivable, allowance for doubtful accounts	$ 3,370	$ 1,145
Property, plant and equipment, accumulated depreciation	571,199	522,424
Intangible assets, Accumulated amortization	449,454	409,328
Unamortized discount and debt issuance costs	$ 9,620	$ 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	135,238,325	134,929,768
Common stock, shares outstanding	135,035,925	134,727,368
Treasury stock, shares outstanding	202,400	202,400