Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 29, 2018	Sep. 29, 2018	Dec. 30, 2017
Accounts receivable allowance for doubtful accounts	$ 18,030	$ 24,125	$ 20,481
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01
Common Stock
Common stock, shares outstanding (in shares)	12,145,135	12,145,135	12,160,023
Class A Common Stock
Common stock, shares outstanding (in shares)	44,059,803	43,953,265	38,029,367
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01
Class B Common Stock
Common stock, shares outstanding (in shares)	1,652,262	1,652,262	1,652,262
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01