Option Activity (Detail) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 30, 2016 USD ($) $ / shares shares
Share-Based Compensation Arrangement By Share-Based Payment Award [Line Items]
Number of shares outstanding, Options Balance | shares	285,000	[1]
Number of shares outstanding, Options Granted | shares	64,000	[1]
Number of shares outstanding, Options forfeited and expired | shares	0	[1]
Number of shares outstanding, Options Exercised | shares	(30,000)	[1]
Number of shares outstanding, awards balance: | shares	319,000	[1]
Number of shares outstanding, Exercisable | shares	188,750
Weighted-average exercise price, Options Balance | $ / shares	$ 26.42	[1]
Weighted-average exercise price, Options Granted | $ / shares	48.59	[1]
Weighted-average exercise price, Options forfeited and expired | $ / shares	0	[1]
Weighted-average exercise price, Options Exercised | $ / shares	18.86	[1]
Weighted-average exercise price, Options Balance | $ / shares	31.58	[1]
Weighted-average exercise price, Exercisable | $ / shares	$ 23.83
Weighted average remaining contractual term, Balance	6 years 5 months 19 days	[1]
Weighted average remaining contractual term, Exercisable	5 years 2 months 12 days
Aggregate intrinsic value, Balance | $	$ 9,162	[1]
Aggregate intrinsic value, Exercisable | $	$ 6,884

[1] Does not include restricted stock or employee stock purchase plans.