Summary of Information Regarding Stock Options (Detail) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 29, 2019 USD ($) $ / shares shares
Number of Options
Beginning Balance, number of options | shares	89,114
Exercised, number of options | shares	(22,700)
Ending Balance, number of options | shares	66,414
Weighted Average Exercise Price per Share
Beginning Balance, Weighted Average Exercise Price per Share | $ / shares	$ 50.44
Exercised, Weighted Average Exercise Price per Share | $ / shares	49.45
Ending Balance, Weighted Average Exercise Price per Share | $ / shares	$ 50.77
Options Exercisable, Number of Options
Options exercisable at the ending, Number of Options | shares	66,414
Options Exercisable, Weighted Average Exercise Price per Share
Options exercisable at the ending, Weighted Average Exercise Price per Share | $ / shares	$ 50.77
Weighted Average Remaining Contractual Term (years)
Options outstanding at June 29, 2019	2 years 8 months 12 days
Options exercisable at June 29, 2019	2 years 8 months 12 days
Aggregate Intrinsic Value
Options outstanding at June 29, 2019 | $	$ 3,800
Options exercisable at June 29, 2019 | $	$ 3,800