CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Earnings	Noncontrolling Interest	Total
Beginning balance at Dec. 26, 2015	$ 20,142	$ 171,562	$ 565,636	$ (4,585)	$ 13,654	$ 766,409
Increase (Decrease) in Stockholders' Equity
Net earnings			80,429		2,828	83,257
Foreign currency translation adjustment				(620)	(1,252)	(1,872)
Unrealized gain (loss) on investment & foreign currency				351		351
Distributions to noncontrolling interest					(3,160)	(3,160)
Additional purchases of noncontrolling interest		855			(1,955)	(1,100)
Cash dividends $0.450 and $0.420 per share (periods ending September 30, 2017 and September 24, 2016, respectively)			(8,529)			(8,529)
Issuance of 5,975 and 5,195 shares under employee stock plans (periods ending September 30, 2017 and September 24, 2016, respectively)	5	390				395
Issuance of 142,775 and 133,293 shares under stock grant programs (periods ending September 30, 2017 and September 24, 2016, respectively)	133	5,143				5,276
Issuance of 49,160 and 50,742 shares under deferred compensation plans (periods ending September 30, 2017 and September 24, 2016, respectively)	51	(51)
Expense associated with share-based compensation arrangements		1,568				1,568
Accrued expense under deferred compensation plans		4,495				4,495
Ending balance at Sep. 24, 2016	20,331	183,962	637,536	(4,854)	10,115	847,090
Beginning balance at Dec. 31, 2016	20,342	185,333	649,135	(5,630)	11,286	860,466
Increase (Decrease) in Stockholders' Equity
Net earnings			88,397		2,480	90,877
Foreign currency translation adjustment				4,325	1,382	5,707
Unrealized gain (loss) on investment & foreign currency				434		434
Distributions to noncontrolling interest					(3,272)	(3,272)
Additional purchases of noncontrolling interest					2,409	2,409
Cash dividends $0.450 and $0.420 per share (periods ending September 30, 2017 and September 24, 2016, respectively)			(9,208)			(9,208)
Issuance of 5,975 and 5,195 shares under employee stock plans (periods ending September 30, 2017 and September 24, 2016, respectively)	6	470				476
Issuance of 142,775 and 133,293 shares under stock grant programs (periods ending September 30, 2017 and September 24, 2016, respectively)	143	7,037				7,180
Issuance of 49,160 and 50,742 shares under deferred compensation plans (periods ending September 30, 2017 and September 24, 2016, respectively)	49	(49)
Repurchase of 148,580 shares	(149)		(12,827)			(12,976)
Expense associated with share-based compensation arrangements		1,978				1,978
Accrued expense under deferred compensation plans		6,009				6,009
Ending balance at Sep. 30, 2017	$ 20,391	$ 200,778	$ 715,497	$ (871)	$ 14,285	$ 950,080