Consolidated Statements of Equity - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	AOCI Attributable to Parent [Member]	Retained Earnings [Member]	Noncontrolling Interest [Member]	Total
Stockholder's equity | Scenario, Previously Reported [Member]	$ 225	$ 223,425	$ (2,353)	$ 20,417	$ 445,059	$ 143	$ 686,916
Stockholder's equity | Restatement Adjustment [Member]					(2,028)		(2,028)
Stockholder's equity	225	223,425	(2,353)	20,417	443,031	143	684,888
Total shareholders’ equity | Scenario, Previously Reported [Member]	225	223,425	(2,353)	20,417	445,059	143	686,916
Total shareholders’ equity | Restatement Adjustment [Member]					(2,028)		(2,028)
Total shareholders’ equity	225	223,425	(2,353)	20,417	443,031	143	684,888
Stockholder's equity | Scenario, Previously Reported [Member]	225	223,425	(2,353)	20,417	445,059	143	727,665
Stockholder's equity | Restatement Adjustment [Member]					(2,028)		(3,346)
Stockholder's equity	225	223,425	(2,353)	20,417	443,031	143	724,319
Total shareholders’ equity | Scenario, Previously Reported [Member]	225	223,425	(2,353)	20,417	445,059	143	727,665
Total shareholders’ equity | Restatement Adjustment [Member]					(2,028)		(3,346)
Total shareholders’ equity	225	223,425	(2,353)	20,417	443,031	143	724,319
Balance (Scenario, Previously Reported [Member]) at Dec. 28, 2013	225	223,425	(2,353)	20,417	445,059	143	686,916
Balance (Restatement Adjustment [Member])					(2,028)		(2,028)
Balance at Dec. 28, 2013	225	223,425	(2,353)	20,417	443,031	143	684,888
Comprehensive income:
Net income | Scenario, Previously Reported [Member]							99,418
Net income | Restatement Adjustment [Member]							(1,318)
Net income					98,100		98,100
Pension and postemployment liability adjustments (net of tax of $1,302, $106 and $6,308, respectively)				(12,475)			(12,475)
Unrealized gain (loss) on investments				1,398			1,398
Activity during period				(30,466)			(30,466)
Comprehensive income | Scenario, Previously Reported [Member]							57,875
Comprehensive income | Restatement Adjustment [Member]							(1,318)
Comprehensive income							56,557
Stock-based compensation		6,926					6,926
Withheld			(2,655)				(2,655)
Purchase of common stock	(2)	(565)	(13,716)				(14,283)
Stock options exercised	3	14,058					14,061
Cash dividends paid					(21,175)		(21,175)
Balance (Scenario, Previously Reported [Member]) at Dec. 27, 2014							727,665
Balance (Restatement Adjustment [Member])							(3,346)
Balance at Dec. 27, 2014	226	243,844	(18,724)	(21,126)	519,956	143	724,319
Comprehensive income:
Reclassification of pension settlement costs to expense (net of tax of $0, $11,742 and $0, respectively)
Pension and postemployment reclassification adjustments, (net of tax of $0, $746 and $0, respectively)
Stockholder's equity | Scenario, Previously Reported [Member]							727,665
Stockholder's equity | Restatement Adjustment [Member]							(3,346)
Stockholder's equity	226	243,844	(18,724)	(21,126)	519,956	143	724,319
Total shareholders’ equity | Scenario, Previously Reported [Member]							727,665
Total shareholders’ equity | Restatement Adjustment [Member]							(3,346)
Total shareholders’ equity	226	243,844	(18,724)	(21,126)	519,956	143	724,319
Stockholder's equity | Scenario, Previously Reported [Member]							744,198
Stockholder's equity | Restatement Adjustment [Member]							(4,946)
Stockholder's equity	226	243,844	(18,724)	(21,126)	519,956	143	739,252
Total shareholders’ equity | Scenario, Previously Reported [Member]							744,198
Total shareholders’ equity | Restatement Adjustment [Member]							(4,946)
Total shareholders’ equity	226	243,844	(18,724)	(21,126)	519,956	143	739,252
Net income | Scenario, Previously Reported [Member]							82,466
Net income | Restatement Adjustment [Member]							(1,600)
Net income					80,866		80,866
Pension and postemployment liability adjustments (net of tax of $1,302, $106 and $6,308, respectively)				(1,761)			(1,761)
Unrealized gain (loss) on investments				793			793
Activity during period				(46,231)			(46,231)
Comprehensive income | Scenario, Previously Reported [Member]							57,921
Comprehensive income | Restatement Adjustment [Member]							(1,600)
Comprehensive income							56,321
Stock-based compensation		7,782					7,782
Withheld			(2,727)				(2,727)
Purchase of common stock	(4)	(1,221)	(30,027)				(31,252)
Stock options exercised	2	9,148					9,150
Cash dividends paid					(24,341)		(24,341)
Balance (Scenario, Previously Reported [Member]) at Jan. 02, 2016							744,198
Balance (Restatement Adjustment [Member])							(4,946)
Balance at Jan. 02, 2016	224	259,553	(32,766)	(45,671)	557,769	143	739,252
Comprehensive income:
Reclassification of pension settlement costs to expense (net of tax of $0, $11,742 and $0, respectively)				21,124			21,124
Pension and postemployment reclassification adjustments, (net of tax of $0, $746 and $0, respectively)				1,530			1,530
Retirement of treasury stock			18,712		(18,712)
Stockholder's equity | Scenario, Previously Reported [Member]							744,198
Stockholder's equity | Restatement Adjustment [Member]							(4,946)
Stockholder's equity	224	259,553	(32,766)	(45,671)	557,769	143	739,252
Total shareholders’ equity | Scenario, Previously Reported [Member]							744,198
Total shareholders’ equity | Restatement Adjustment [Member]							(4,946)
Total shareholders’ equity	224	259,553	(32,766)	(45,671)	557,769	143	739,252
Stockholder's equity | Scenario, Previously Reported [Member]							744,198
Stockholder's equity | Restatement Adjustment [Member]							(4,946)
Stockholder's equity	224	259,553	(32,766)	(45,671)	557,769	143	814,931
Total shareholders’ equity | Scenario, Previously Reported [Member]							744,198
Total shareholders’ equity | Restatement Adjustment [Member]							(4,946)
Total shareholders’ equity	224	259,553	(32,766)	(45,671)	557,769	143	814,931
Net income					104,488		104,488
Pension and postemployment liability adjustments (net of tax of $1,302, $106 and $6,308, respectively)				(3,673)			(3,673)
Unrealized gain (loss) on investments				(815)			(815)
Activity during period				(24,832)			(24,832)
Comprehensive income							75,580
Stock-based compensation		7,471					7,471
Withheld			(3,744)				(3,744)
Stock options exercised	4	24,234					24,238
Cash dividends paid					(27,866)		(27,866)
Balance at Dec. 31, 2016	228	291,258	(36,510)	(74,579)	634,391	143	814,931
Comprehensive income:
Reclassification of pension settlement costs to expense (net of tax of $0, $11,742 and $0, respectively)
Pension and postemployment reclassification adjustments, (net of tax of $0, $746 and $0, respectively)				412			412
Stockholder's equity	228	291,258	(36,510)	(74,579)	634,391	143	814,931
Total shareholders’ equity	$ 228	$ 291,258	$ (36,510)	$ (74,579)	$ 634,391	$ 143	$ 814,931