Capital Transactions - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	0 Months Ended	3 Months Ended		6 Months Ended					0 Months Ended		3 Months Ended		6 Months Ended
	Apr. 29, 2008	Jun. 29, 2014	Jun. 30, 2013	Jun. 29, 2014 Stock Vote	Jun. 30, 2013	Jun. 27, 2014	Jun. 28, 2013	Apr. 29, 2008 Performance Shares [Member]	Mar. 04, 2014 Class B Common Stock [Member]	Mar. 05, 2013 Class B Common Stock [Member]	Jun. 29, 2014 Class B Common Stock [Member]	Jun. 30, 2013 Class B Common Stock [Member]	Jun. 29, 2014 Class B Common Stock [Member] Vote	Jun. 30, 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	$ 0.50	$ 0.50						$ 0.25	$ 0.25	$ 0.50	$ 0.50
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				$ 1.5	$ 1.2
Share price						$ 74.56	$ 61.15
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