INCOME TAXES - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 02, 2016	Jan. 03, 2015
Federal:
Current	$ (71)	$ (469)
Deferred	737	(2,513)
State:
Current	2	5
Deferred	113	(507)
Total	$ 781	$ (3,484)
Difference between tax rate for continuing operations on income or loss for financial statement purposes and federal statutory tax rate
Statutory tax rate (as a percent)	34.00%	(34.00%)
Percentage depletion	(4.00%)	(1.00%)
Non-deductible expenses (as a percent)	2.00%	0.40%
Valuation allowance for tax assets (as a percent)	(4.90%)	(0.40%)
State income taxes, net of federal benefit (as a percent)	5.70%	(4.10%)
Expiring charitable contributions (as a percent)	2.60%
Other (as a percent)	0.20%	0.10%
Total (as a percent)	35.60%	(39.00%)
Current statutory federal and states tax rates (as a percent)	37.96%
Deferred tax assets
Reserves for self-insured losses	$ 605	$ 655
Accrued reclamation	2,154	2,055
Unfunded supplemental profit sharing plan liability	379	444
Asset valuation reserves	317	432
Future state tax credits	789	789
Net state operating loss carryforwards	252	369
Federal AMT carryforward	481	268
Federal NOL carryforward	16	925
Other	100	197
Valuation allowance	(73)	(180)
Total deferred tax assets	5,020	5,954
Deferred tax liabilities
Depreciation	841	1,146
Deferred development	563	245
Other	467	643
Total deferred tax liabilities	1,871	2,034
Net deferred tax asset	$ 3,149	$ 3,920