Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 30, 2017
Statement Of Financial Position [Abstract]
Allowances for accounts receivable	$ 25,889	$ 25,971
Allowances for vendor receivables	$ 3,490	$ 2,934
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	600,000,000	600,000,000
Common stock, shares issued	215,942,000	214,963,000
Common stock, shares outstanding	215,942,000	214,963,000