Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock Common Class A	Common Stock Common Class B	Additional Paid-in Capital	Accumulated Other Comprehensive (Loss) Income, net of tax	Retained Earnings
Balance (in shares) at Dec. 29, 2012		8,704,000	4,107,000
Balance at Dec. 29, 2012	$ 245,091	$ 87	$ 41	$ 157,305	$ (883)	$ 88,541
Net Income	70,392					70,392
Stock options exercised and restricted shares activities, including tax benefit of $5,282 in 2013, $17,353 in 2014 and $15,350 in 2015 (in shares)		132,000
Stock options exercised and restricted shares activities, including tax benefit of $5,282 in 2013, $17,353 in 2014 and $15,350 in 2015	8,403	$ 1		8,402
Stock-based compensation expense	$ 7,318			7,318
Repurchase of Class A Common Stock (in shares)	(195,728)	(196,000)
Repurchase of Class A Common Stock	$ (29,585)	$ (1)				(29,584)
Conversion from Class B to Class A (in shares)		145,000	(145,000)
Conversion from Class B to Class A		$ 1	$ (1)
Defined benefit plans liability adjustment, net of tax of ($296) in 2013, $455 in 2014 and ($142) in 2015	466				466
Balance (in shares) at Dec. 28, 2013		8,785,000	3,962,000
Balance at Dec. 28, 2013	302,085	$ 88	$ 40	173,025	(417)	129,349
Net Income	90,743					90,743
Stock options exercised and restricted shares activities, including tax benefit of $5,282 in 2013, $17,353 in 2014 and $15,350 in 2015 (in shares)		351,000
Stock options exercised and restricted shares activities, including tax benefit of $5,282 in 2013, $17,353 in 2014 and $15,350 in 2015	45,030	$ 3		45,027
Stock-based compensation expense	$ 6,857			6,857
Repurchase of Class A Common Stock (in shares)	(29,474)	(29,000)
Repurchase of Class A Common Stock	$ (7,859)					(7,859)
Conversion from Class B to Class A (in shares)		345,000	(345,000)
Conversion from Class B to Class A		$ 4	$ (4)
Defined benefit plans liability adjustment, net of tax of ($296) in 2013, $455 in 2014 and ($142) in 2015	(716)				(716)
Balance (in shares) at Dec. 27, 2014		9,452,000	3,617,000
Balance at Dec. 27, 2014	436,140	$ 95	$ 36	224,909	(1,133)	212,233
Net Income	$ 98,414					98,414
Stock options exercised and restricted shares activities, including tax benefit of $5,282 in 2013, $17,353 in 2014 and $15,350 in 2015 (in shares)	277,645	303,000
Stock options exercised and restricted shares activities, including tax benefit of $5,282 in 2013, $17,353 in 2014 and $15,350 in 2015	$ 58,525	$ 3		58,522
Stock-based compensation expense	$ 6,665			6,665
Repurchase of Class A Common Stock (in shares)	(616,747)	(616,000)	0
Repurchase of Class A Common Stock	$ (138,705)	$ (6)				(138,699)
Conversion from Class B to Class A (in shares)		250,000	(250,000)
Conversion from Class B to Class A		$ 2	$ (2)
Defined benefit plans liability adjustment, net of tax of ($296) in 2013, $455 in 2014 and ($142) in 2015	204				204
Currency translation adjustment	(22)				(22)
Balance (in shares) at Dec. 26, 2015		9,389,000	3,367,000
Balance at Dec. 26, 2015	$ 461,221	$ 94	$ 34	$ 290,096	$ (951)	$ 171,948