Summary of Information Regarding Stock Options (Detail) $ / shares in Units, $ in Thousands	6 Months Ended
	Jul. 01, 2017 USD ($) $ / shares shares
Number of Options
Beginning Balance, number of options | shares	372,561
Exercised, number of options | shares	(114,009)
Forfeited, number of options | shares	(600)
Ending Balance, number of options | shares	257,952
Options exercisable at the ending, Number of Options | shares	237,452
Weighted Average Exercise Price per Share
Beginning Balance, Weighted Average Exercise Price per Share | $ / shares	$ 48.24
Exercised, Weighted Average Exercise Price per Share | $ / shares	46.10
Forfeited, Weighted Average Exercise Price per Share | $ / shares	54.93
Ending Balance, Weighted Average Exercise Price per Share | $ / shares	49.16
Options exercisable at July 1, 2017 | $ / shares	$ 48.53
Weighted Average Remaining Contractual Term (years)
Options outstanding at July 1, 2017	4 years 3 months 19 days
Options exercisable at July 1, 2017	4 years 1 month 6 days
Aggregate Intrinsic Value
Options outstanding at July 1, 2017 | $	$ 9,399
Options exercisable at July 1, 2017 | $	$ 8,802