Capital Transactions - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	0 Months Ended	3 Months Ended		9 Months Ended					0 Months Ended			3 Months Ended		9 Months Ended
	Apr. 29, 2008	Sep. 28, 2014	Sep. 29, 2013	Sep. 28, 2014 Stock Vote	Sep. 29, 2013	Sep. 26, 2014	Sep. 27, 2013	Apr. 29, 2008 Performance Shares [Member]	Mar. 04, 2014 Class B Common Stock [Member]	Mar. 05, 2013 Class B Common Stock [Member]	Apr. 29, 2008 Class B Common Stock [Member]	Sep. 28, 2014 Class B Common Stock [Member]	Sep. 29, 2013 Class B Common Stock [Member]	Sep. 28, 2014 Class B Common Stock [Member] Vote	Sep. 29, 2013 Class B Common Stock [Member]	Apr. 29, 2008 Class B Common Stock [Member]
Schedule of Capitalization, Equity [Line Items]
Number of classes of common stock outstanding				2
Dividend is declared and paid on the Common Stock		$ 0.25	$ 0.25	$ 0.75	$ 0.75							$ 0.25	$ 0.25	$ 0.75	$ 0.75
Number of votes per share				1										20
Performance units authorized								400,000
Term of performance unit award agreement	10 years
Class B Common Stock per performance unit																1
Annual performance units granted											40,000
Maximum overall goal achievement factor																100.00%
Performance Unit Award Agreement expense recognized				$ 2.3	$ 1.9
Share price						$ 75.74	$ 63.36
Performance units awarded									40,000	40,000
Performance units awards settled in cash														19,100	19,880
Increase in total number of shares outstanding														20,900	20,120