Calculation of Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 24, 2017	Sep. 25, 2016	Sep. 24, 2017	Sep. 25, 2016
Basic earnings per common share:
Net income attributable to the Company	$ 21,817	$ 21,467	$ 73,783	$ 70,190
Change in noncontrolling interest redemption value	237	(157)	1,419	342
Net income attributable to participating securities	(89)	(87)	(305)	(288)
Net income attributable to common shareholders	$ 21,965	$ 21,223	$ 74,897	$ 70,244
Weighted average common shares outstanding	36,146	36,989	36,563	37,374
Basic earnings per common share	$ 0.61	$ 0.57	$ 2.05	$ 1.88
Diluted earnings per common share:
Net income attributable to common shareholders	$ 21,965	$ 21,223	$ 74,897	$ 70,244
Weighted average common shares outstanding	36,146	36,989	36,563	37,374
Dilutive effect of outstanding equity awards	435	370	484	338
Diluted weighted average common shares outstanding	36,581	37,359	37,047	37,712
Diluted earnings per common share	$ 0.60	$ 0.57	$ 2.02	$ 1.86
Weighted average antidilutive awards excluded from computation of earnings per share	328	22	261	598