Stock-Based Compensation - Additional Information (Detail) - USD ($)			12 Months Ended
	Dec. 27, 2017	Nov. 15, 2016	Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016	Dec. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, options outstanding (shares)	2,309,103			2,309,103	2,191,728	2,151,214
Common stock, options vested (shares)				1,909,440
Common stock, options unvested (shares)	399,663			399,663
Options to purchase common stock granted (shares)				135,036	347,053
Stock-based compensation expense				$ 1,056,000	$ 1,063,000	$ 539,000
Aggregate intrinsic value of options outstanding	$ 7,300,000			7,300,000
Aggregate intrinsic value of options exercisable	7,300,000			7,300,000
Intrinsic value of options exercised				200,000	900,000	14,900,000
Stock-based compensation expense				600,000	$ 900,000	$ 500,000
Incremental expense from plan modification (less than $0.1 million)				100,000
Unrecognized compensation expense	$ 1,200,000			$ 1,200,000
Unrecognized compensation expense, recognition period				2 years 8 months 13 days
Exercise price equal to the fair market value of the common stock on the date of grant
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options to purchase common stock granted (shares)				135,036	329,673	0
Option vesting period				4 years
Premium Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, options outstanding (shares)	1,563,549			1,563,549
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted, description				Of the total options granted in fiscal 2014, 50% were performance based and vested according to whether certain financial targets were met, and the remaining 50% vested over a term of four.
Authorized number of common stock for issuance (shares)	4,402,240			4,402,240
Number of share available for grant (shares)	359,642			359,642
Weighted average grant date fair value (usd per share)				$ 4.29	$ 4.13
Expected volatility				28.60%
Expected life				5 years 9 months	5 years 9 months
Risk-free interest rates, minimum				1.90%	1.10%
Risk-free interest rates, maximum				2.00%	1.80%
Expected dividends				0.00%	0.00%
Expected volatility, minimum					32.40%
Performance Based Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, options outstanding (shares)	0			0
Common stock, options vested (shares)	80,799	17,380
Stock-based compensation expense				$ 600,000
Options expiration period				10 years
Time Based Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, options outstanding (shares)	2,309,103			2,309,103
Options expiration period				10 years
Restricted Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense				$ 500,000	$ 200,000	$ 100,000
Unrecognized compensation expense, recognition period				3 years 2 months 5 days
Granted (shares)				181,292	29,259
Unrecognized compensation expense	$ 2,300,000			$ 2,300,000
Restricted Shares | Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Option vesting period				3 years
Value of restricted grants				$ 50,000
Restricted Shares | Employees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Option vesting period				4 years
Forecast | Performance Based Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, options vested (shares)			17,378