Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 30, 2017
Assets:
Property, plant and equipment, accumulated depreciation	$ 1,147,349	$ 1,075,448
Intangible assets, accumulated amortization	$ 390,866	$ 383,836
Stockholders’ equity:
Common stock, par value (in usd per share)	$ 0.01	$ 0.01
Common stock, shares authorized	250,000,000	250,000,000
Common stock, shares issued	168,074,119	167,892,500
Treasury stock, shares	3,420,210	3,239,063