Income Taxes (Details) - USD ($)		3 Months Ended	12 Months Ended
	Jan. 01, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current:
Federal			$ (2,461,000)	$ (1,835,000)	$ (2,456,000)
State			(683,000)	(562,000)	(794,000)
Total			(3,144,000)	(2,397,000)	(3,250,000)
Deferred:
Federal			929,000	4,353,000	520,000
State			37,000	(67,000)	141,000
Total			966,000	4,286,000	661,000
Total income tax (expense) benefit			$ (2,178,000)	$ 1,889,000	$ (2,589,000)
Reconciliation of the effective income tax rate with the applicable statutory federal income tax rate
Federal tax at statutory rate (as a percent)	21.00%	21.00%	21.00%	35.00%	35.00%
State taxes, net of federal benefit (as a percent)			19.80%	8.80%	36.00%
Valuation allowance (as a percent)			(14.20%)	(2.50%)	(29.20%)
Tax Cuts and Jobs Act (as a percent)				(69.30%)
Other (as a percent)			(2.60%)	(0.90%)	(1.30%)
Effective income tax rate (as a percent)			24.00%	(28.90%)	40.50%
Deferred income tax assets:
Accruals not currently deductible for income taxes		$ 1,906,000	$ 1,524,000	$ 1,906,000
Net operating loss carry-forwards		8,928,000	7,602,000	8,928,000
Total deferred income tax assets		10,834,000	9,126,000	10,834,000
Valuation allowance		(8,291,000)	(7,005,000)	(8,291,000)
Net deferred income tax assets		2,543,000	2,121,000	2,543,000
Deferred income tax liabilities:
Depreciation		(11,216,000)	(10,492,000)	(11,216,000)
Total deferred income tax liabilities		(11,216,000)	(10,492,000)	(11,216,000)
Net deferred income tax liability		(8,673,000)	(8,371,000)	(8,673,000)
Amounts recognized in the consolidated balance sheets:
Noncurrent deferred income tax liabilities		$ (8,673,000)	$ (8,371,000)	$ (8,673,000)