Capital Stock - Summary of Stock Option Activity (Detail) - USD ($)	12 Months Ended
	Dec. 30, 2017	Dec. 31, 2016	Dec. 26, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning Balance, Shares	101,084	40,000	75,000
Granted, Shares	58,024	61,084
Exercised, Shares	(32,751)		(35,000)
Cancelled, Shares	(3,810)
Ending Balance, Shares	122,547	101,084	40,000
Options Exercisable, Shares	22,520
Options Exercisable, Option Price per Share	$ 31.07
Beginning Balance, Weighted Average Price	29.52	$ 6.86	$ 7.28
Granted, Weighted Average Price	78.58	44.36
Exercised, Weighted Average Price	7.69		7.76
Cancelled, Weighted Average Price	56.72
Ending Balance, Weighted Average Price	$ 57.74	29.52	6.86
Ending Balance, Weighted Average Remaining Terms (years)	3 years 7 months 6 days
Options Exercisable, Weighted Average Remaining Terms (years)	2 years 7 months 6 days
Ending Balance, Aggregate Intrinsic Value	$ 1,402,012
Options Exercisable, Aggregate Intrinsic Value	$ 677,188
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning Balance, Option Price per Share	$ 5.67	5.67	5.05
Option price per share, Granted	69.02	41.59
Option Price per Share, Exercised	6.90		5.05
Option Price per Share, Cancelled	41.59
Ending Balance, Option Price per Share	5.67	5.67	5.67
Options Exercisable, Option Price per Share	5.67
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning Balance, Option Price per Share	53.32	7.74	19.37
Option price per share, Granted	82.59	53.32
Option Price per Share, Exercised	41.59		19.37
Option Price per Share, Cancelled	78.64
Ending Balance, Option Price per Share	82.59	$ 53.32	$ 7.74
Options Exercisable, Option Price per Share	$ 53.32