Long-Term Debt and Capital Lease Obligations (Details Textual) - USD ($)	1 Months Ended		7 Months Ended	12 Months Ended
	Mar. 29, 2018	Jun. 30, 2016	Dec. 31, 2015	Dec. 28, 2017	Dec. 29, 2016	May 28, 2015	Feb. 28, 2013
Debt Instrument, Periodic Payment, Total				$ 39,110
Senior Notes, Noncurrent				$ 129,143,000	$ 90,286,000
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate				5.75%
Line of Credit Facility, Commitment Fee Percentage				0.20%
Line of Credit Facility, Remaining Borrowing Capacity				$ 91,000,000
Interest Paid, Net			$ 5,220,000	11,453,000	9,105,000	$ 9,353,000
Derivative, Amount of Hedged Item							$ 25,000,000
Derivative Liability, Notional Amount				25,000,000
Derivative Instruments Loss Reclassified From Accumulated Income Effective Portion Net Of Tax		$ 96,000
Derivative Instruments, Loss Reclassified from Accumulated OCI into Income, Effective Portion		$ 159,000
Commitment Minimum Lease Payments				6,163,000
Obligation To Be Reduced In Next 12 Months				5,657,000
Line of Credit Facility, Current Borrowing Capacity				35,000,000
Digital Systems [Member]
Capital Leases, Lessee Balance Sheet, Assets by Major Class, Accumulated Depreciation				34,471,000	28,294,000
Capital Leases, Balance Sheet, Assets by Major Class, Net				45,510,000	45,510,000
Furniture and Fixtures [Member]
Capital Leased Assets, Gross				1,712,000	1,712,000
Capital Leases, Balance Sheet, Assets by Major Class, Net				255,000
Building and Building Improvements [Member]
Capital Leased Assets, Gross				25,648,000	$ 15,799,000
Capital Leases, Balance Sheet, Assets by Major Class, Net				$ 2,300,000
Subsequent Event [Member]
Derivative, Amount of Hedged Item	$ 50,000,000
Subsequent Event [Member] | First Interest Rate Swap [Member]
Derivative, Fixed Interest Rate	2.559%
Derivative, Notional Amount	$ 25,000,000
Derivative, Maturity Date	Mar. 01, 2021
Subsequent Event [Member] | Second Interest Rate Swap [Member]
Derivative, Fixed Interest Rate	2.687%
Derivative, Notional Amount	$ 25,000,000
Derivative, Maturity Date	Mar. 01, 2023
Senior Notes [Member]
Long-term Debt, Weighted Average Interest Rate				4.70%	5.10%
Minimum [Member] | Senior Notes [Member]
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate				4.02%
Maximum [Member] | Senior Notes [Member]
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate				6.55%
Revolving Credit Facility [Member]
Long-term Line of Credit				$ 130,000,000
Debt Instrument, Interest Rate, Effective Percentage				2.67%	1.83%
Credit Agreement [Member]
Line of Credit Facility, Maximum Borrowing Capacity				$ 225,000,000
Interest Rate Swap [Member]
Derivative, Fixed Interest Rate							0.96%
Derivative, Variable Interest Rate				1.56%
Decrease In Interest Expense				$ 7,000
Mortgage Notes [Member]
Debt, Weighted Average Interest Rate				4.22%	4.70%
Mortgage Notes [Member] | Minimum [Member]
Interest Rate of Unsecured Term Note				3.00%
Mortgage Notes [Member] | Maximum [Member]
Interest Rate of Unsecured Term Note				5.03%