Consolidated Statements of Cash Flows - USD ($)	3 Months Ended				6 Months Ended		9 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jul. 01, 2018	Apr. 01, 2018	Jun. 30, 2019	Jul. 01, 2018	Oct. 02, 2016	Sep. 27, 2015	Dec. 30, 2018	Dec. 31, 2017
Cash and cash equivalents	$ 113,636,000		$ 88,887,000		$ 113,636,000	$ 88,887,000			$ 63,170,000
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	113,818,000		89,094,000		113,818,000	89,094,000			63,321,000	$ 67,312,000
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)	(8,734,000)	$ 21,246,000	(8,965,000)	$ 12,223,000	12,512,000	3,256,000
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	24,118,000		25,493,000		48,452,000	52,065,000
Deferred income taxes					(309,000)	(3,626,000)
Stock-based compensation expense			163,000		2,096,000	227,000
Amortization of lease related liabilities					0	(508,000)
Amortization of original issue discount and deferred debt financing costs					2,117,000	2,226,000
Loss on asset disposals, net					1,983,000	2,038,000
Asset Impairment Charges	1,285,000		1,591,000		1,285,000	1,591,000	$ 772,000	$ 0
Noncash Rent Expense					1,663,000	2,931,000
IncreaseDecreaseinLeaseRelatedLiabilities					(945,000)	0
Operating Lease, Payments					43,888,000
Other adjustments					(270,000)	348,000
Changes in operating assets and liabilities:
Increase (Decrease) in Receivables					4,200,000	2,380,000
Inventories					(1,771,000)	1,314,000
Prepaid expenses					(1,925,000)	(7,430,000)
Accounts payable					4,045,000	1,439,000
Accrued expenses					1,059,000	1,134,000
Other liabilities					2,619,000	(1,089,000)
Income taxes receivable					745,000	14,000
Increase (Decrease) in Income Taxes Payable					13,516,000	4,964,000
Increase (Decrease) in Deferred Landlord Contributions					0	1,751,000
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability					5,940,000
Net Cash Provided by (Used in) Operating Activities					91,072,000	65,025,000
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property and equipment					(34,342,000)	(36,808,000)
Payments to Develop Software					(609,000)	(1,022,000)
Proceeds from Sale of Property, Plant, and Equipment					141,000	412,000
Net cash used in investing activities					(34,810,000)	(37,418,000)
CASH FLOWS FROM FINANCING ACTIVITIES:
Repayments on senior term loan					(3,800,000)	(3,800,000)
Payments of Financing Costs					0	(395,000)
Payments on financing lease obligations					(344,000)	(295,000)
Sale Leaseback Transaction, Payments, Financing Activities					(1,619,000)	(1,384,000)
Net cash used in financing activities					(5,763,000)	(5,874,000)
Effect of foreign exchange rate changes on cash					(2,000)	49,000
Change in cash, cash equivalents and restricted cash					50,497,000	21,782,000
Cash, cash equivalents and restricted cash at end of period	113,818,000		89,094,000		113,818,000	89,094,000
SUPPLEMENTAL CASH FLOW INFORMATION:
Interest paid					(36,994,000)	(35,906,000)
Income taxes (refunded) paid, net					(8,016,000)	421,000
NON-CASH INVESTING AND FINANCING ACTIVITIES:
Accrued construction costs					324,000	1,352,000
Restricted cash	$ 182,000		$ 207,000		$ 182,000	$ 207,000			$ 151,000