Shareholders' Deficit - Share Repurchase (Details) - USD ($) $ / shares in Units, shares in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Nov. 30, 2018	Sep. 25, 2019	Sep. 26, 2018	Sep. 25, 2019	Sep. 26, 2018	Jun. 26, 2019	Dec. 26, 2018	Jun. 27, 2018	Dec. 27, 2017	Oct. 31, 2017
Equity, Class of Treasury Stock [Line Items]
Payments for repurchase of common stock				$ 50,649,000	$ 37,108,000
Purchase of treasury stock		$ 12,807,000	$ 8,563,000	$ 50,804,000	$ 37,407,000
Number of accumulated shares repurchased		50,073		50,073			47,052
Treasury Stock [Member]
Equity, Class of Treasury Stock [Line Items]
Purchase of treasury stock (in shares)		589	574	2,632	2,437
Purchase of treasury stock		$ 12,807,000	$ 8,563,000	$ 50,804,000	$ 37,407,000
Number of accumulated shares repurchased		50,073	45,588	50,073	45,588	49,484	47,052	45,014	43,151
Share Repurchase Program 2017 [Member]
Equity, Class of Treasury Stock [Line Items]
Share repurchase, authorized amount										$ 200,000,000
Purchase of treasury stock (in shares)				2,600
Purchase of treasury stock				$ 50,800,000
Remaining shares to be repurchased		$ 77,600,000		$ 77,600,000
Number of accumulated shares repurchased		7,200		7,200
Value of shares repurchased		$ 122,400,000		$ 122,400,000
Accelerated Share Repurchase 2018 [Member]
Equity, Class of Treasury Stock [Line Items]
Share repurchase, authorized amount	$ 25,000,000
Payments for repurchase of common stock	$ 25,000,000
Purchase of treasury stock (in shares)	1,100
Purchase of treasury stock	$ 18,200,000
Remaining shares to be repurchased							$ 6,800,000
Volume-weighted average price (in dollars per share)				$ 17.04
Accelerated Share Repurchase 2018 [Member] | Treasury Stock [Member]
Equity, Class of Treasury Stock [Line Items]
Purchase of treasury stock (in shares)				389
Purchase of treasury stock				$ 6,800,000