Description of Business and Summary of Significant Accounting Policies (Details Textual) - USD ($)	12 Months Ended
	Dec. 27, 2018	Dec. 28, 2017	Dec. 29, 2016	Dec. 28, 2018	Dec. 29, 2017
Summary of Significant Accounting Policies [Line Items]
Depreciation	$ 61,470,000	$ 51,542,000	$ 42,085,000
Percentage Of Cash Dividends	110.00%
Senior Notes, Noncurrent	$ 118,000,000	129,143,000
Inventory, Net	$ 4,138,000	4,062,000
Concentration Risk, Labor Subject to Collective Bargaining Arrangements	As of December 27, 2018, 7% of the Company’s employees were covered by a collective bargaining agreement, of which 96% were covered by an agreement that will expire within one year. As of December 28, 2017, 7% of the Company’s employees were covered by a collective bargaining agreement, of which 1% were covered by an agreement that expired within one year.
Interest Costs Capitalized	$ 65,000	400,000	277,000
Amortization of Debt Issuance Costs	$ 287,000	$ 308,000	$ 303,000
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	15,500	250,000	14,000
Net Cash Provided by (Used in) Investing Activities	$ (59,267,000)	$ (101,206,000)	$ (141,140,000)
Reimbursed Costs	34,285,000	30,838,000	30,460,000
Senior Notes [Member]
Summary of Significant Accounting Policies [Line Items]
Senior Notes, Noncurrent	$ 118,000,000
Accounting standard update 2018 02 [Member] | Retained Earnings [Member]
Summary of Significant Accounting Policies [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption					$ 1,574,000
Accounting Standards Update 2016-18 [Member]
Summary of Significant Accounting Policies [Line Items]
Net Cash Provided by (Used in) Investing Activities		967,000	12,553,000
Accounting Standards Update 2016-01 [Member]
Summary of Significant Accounting Policies [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption					0
Accounting Standards Update 2016-01 [Member] | Retained Earnings [Member]
Summary of Significant Accounting Policies [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption					$ (11,000)
Accounting Standards Update 2017-07 [Member]
Summary of Significant Accounting Policies [Line Items]
Operating Expenses		$ 1,712,000	$ 1,519,000
Minimum [Member]
Summary of Significant Accounting Policies [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share	$ 38.51	$ 31.20	$ 23.37
Operating Leases, Future Minimum Payments Due				$ 75,000,000
Maximum [Member]
Summary of Significant Accounting Policies [Line Items]
Equity Method Investment, Ownership Percentage	50.00%
Antidilutive Securities Excluded from Computation of Earnings Per Share	$ 41.35	$ 31.55	$ 31.55
Operating Leases, Future Minimum Payments Due				$ 100,000,000
Corporate Joint Venture One [Member] | Minimum [Member]
Summary of Significant Accounting Policies [Line Items]
Ownership Interest In Joint Ventures	50.00%
Corporate Joint Venture Two [Member]
Summary of Significant Accounting Policies [Line Items]
Ownership Interest In Joint Ventures	50.00%
Fair Value, Inputs, Level 1 [Member]
Summary of Significant Accounting Policies [Line Items]
Trading Securities, Fair Value Disclosure	$ 5,302,000	$ 4,053,000
Fair Value, Inputs, Level 2 [Member]
Summary of Significant Accounting Policies [Line Items]
Senior Notes, Noncurrent	110,022,000
Interest Rate Fair Value Hedge Liability at Fair Value	$ 205,000
Interest Rate Fair Value Hedge Asset at Fair Value		$ 13,000