Option Activity (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Jan. 02, 2015		Jan. 03, 2014
Share-Based Compensation Arrangement By Share-Based Payment Award [Line Items]
Number of shares outstanding, Options Granted	22,500	[1]
Number of shares outstanding, Options forfeited and expired	0	[1]
Number of shares outstanding, Options Exercised	(42,000)	[1]
Number of shares outstanding, awards balance:	197,500	[1]	217,000	[1]
Number of shares outstanding, Vested and expected to vest	195,507	[1]
Number of shares outstanding, Exercisable	134,375	[1]
Weighted-average exercise price, Options Granted	$ 70.80	[1]
Weighted-average exercise price, Options forfeited and expired	$ 0	[1]
Weighted-average exercise price, Options Exercised	$ 22.86	[1]
Weighted-average exercise price, Options Balance	$ 38.43	[1]	$ 32.06	[1]
Weighted-average exercise price, Options Vested and Expected to Vest	$ 38.22	[1]
Weighted-average exercise price, Exercisable	$ 30.35	[1]
Weighted average remaining contractual term, Balance	5 years 10 months 6 days	[1]
Weighted average remaining contractual term, Vested and Expected to Vest	5 years 9 months 29 days	[1]
Weighted average remaining contractual term, Exercisable	4 years 9 months 29 days	[1]
Aggregate intrinsic value, Balance	$ 8,426	[1]
Aggregate intrinsic value, Vested and Expected to Vest	8,382	[1]
Aggregate intrinsic value, Exercisable	$ 6,819	[1]

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