Option Activity (Detail) $ / shares in Units, $ in Thousands	12 Months Ended
	Jan. 01, 2016 USD ($) $ / shares shares
Share-Based Compensation Arrangement By Share-Based Payment Award [Line Items]
Number of shares outstanding, Options Balance | shares	395,000	[1]
Number of shares outstanding, Options Granted | shares	40,000	[1]
Number of shares outstanding, Options forfeited and expired | shares	0	[1]
Number of shares outstanding, Options Exercised | shares	(150,000)	[1]
Number of shares outstanding, awards balance: | shares	285,000	[1]
Number of shares outstanding, Vested and expected to vest | shares	281,263	[1]
Number of shares outstanding, Exercisable | shares	171,250	[1]
Weighted-average exercise price, Options Balance | $ / shares	$ 19.21	[1]
Weighted-average exercise price, Options Granted | $ / shares	44.20	[1]
Weighted-average exercise price, Options forfeited and expired | $ / shares	0	[1]
Weighted-average exercise price, Options Exercised | $ / shares	12.18	[1]
Weighted-average exercise price, Options Balance | $ / shares	26.42	[1]
Weighted-average exercise price, Options Vested and Expected to Vest | $ / shares	26.28	[1]
Weighted-average exercise price, Exercisable | $ / shares	$ 20.89	[1]
Weighted average remaining contractual term, Balance	6 years 7 months 2 days	[1]
Weighted average remaining contractual term, Vested and Expected to Vest	6 years 6 months 25 days	[1]
Weighted average remaining contractual term, Exercisable	5 years 7 months 24 days	[1]
Aggregate intrinsic value, Balance | $	$ 6,706
Aggregate intrinsic value, Vested and Expected to Vest | $	6,657
Aggregate intrinsic value, Exercisable | $	$ 4,977

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