SHARE-BASED COMPENSATION- Stock Options (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 25, 2016	Dec. 27, 2015	Dec. 28, 2014	Dec. 31, 2017	May 16, 2017	Dec. 25, 2016	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Document Period End Date	Dec. 31, 2017
Capital shares reserved for future issuance					990,514
Unamortized stock compensation expense					$ 600
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Exercised	(13,800)	(87,655)	0
Options exercisable (in shares)					498,611		395,911
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Options exercisable at beginning of period (in dollars per share) (in shares)	$ 8.74	$ 8.01			$ 8.74		$ 8.01
Options exercisable at ending of period (in dollars per share) (in shares)	$ 8.74	$ 8.01
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Options exercisable, weighted average remaining contractual term	6 years 9 months 15 days	7 years 6 months 22 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Intrinsic Value [Abstract]
Options exercisable at beginning of period	$ 3,640	$ 2,965			$ 3,640		$ 2,965
Options exercisable at ending of period	3,640	2,965
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost related to stock awards	$ 400	$ 300	$ 300
Unamortized stock compensation expense, recognition period	2 years 5 months 22 days
Conversion of stock, shares issued	5,221	55,974	0
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Weighted-average fair value of warrants	$ 3.94	$ 4.05	$ 1.83
Weighted-average risk-free interest rate	1.80%	1.10%	1.50%
Weighted-average dividend yield	100.00%	100.00%	100.00%
Weighted-average volatility factor	43.20%	43.20%	43.20%
Weighted-average expected life	6 years	6 years	6 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options outstanding at beginning of period (in shares)	678,411	775,666	585,466
Granted	128,000	50,000	286,000
Exercised	(28,800)	(103,055)	(50,800)
Forfeited / Canceled	(12,200)	(44,200)	(45,000)
Options outstanding at ending of period (in shares)	765,411	678,411	775,666	585,466
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Options outstanding at beginning of period (in dollars per share)	$ 8.95	$ 8.19	$ 6.52
Granted	16.76	17.46	11.03
Exercised	7.71	6.91	6.66
Forfeited / Canceled	11.00	9.94	6.25
Options outstanding at ending of period (in dollars per share)	$ 10.27	$ 8.95	$ 8.19	$ 6.52
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Options outstanding, weighted average remaining contractual term	7 years 3 months 7 days	7 years 10 months 6 days	8 years 8 months 1 day	9 years 1 month 17 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Intrinsic Value [Abstract]
Options outstanding at beginning of period	$ 4,511	$ 5,246	$ 3,204
Options outstanding at ending of period	$ 4,521	$ 4,511	$ 5,246	$ 3,204
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Nonvested, number of shares					266,800		282,500
Nonvested options, weighted average grant date fair value					$ 3.09		$ 2.57
Long Term Incentive Plan 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Capital shares reserved for future issuance								900,000
Additional capital shares reserved for future issuance						250,000
Long Term Incentive Plan 2013 | Vested Immediately
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting rights, percentage	20.00%
Long Term Incentive Plan 2013 | Vesting Over Four Years
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting rights, percentage	20.00%
Long Term Incentive Plan 2013 | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period, options (in years)	10 years