Long-Term Debt (Narrative) (Details) - USD ($) | Nov. 01, 2019 | Jul. 31, 2020 | Dec. 26, 2020 | Dec. 28, 2019 | Jun. 30, 2013 | Dec. 31, 2010 |
Debt Instrument [Line Items] | | | | | | |
Debt extinguishment costs | | | | $ (3,719,209) | | |
Loan redeption period after rdemption notice | 30 days | | | | | |
Annual amount of redemption of bonds | | | $ 4,500,000 | | | |
Mandatory bonds redemption beginning period | | | Jan. 1, 2014 | | | |
Mandatory bonds redemption period end date | | | Sep. 26, 2026 | | | |
Other comprehensive income, net of income taxes | | | $ 2,763,738 | 2,848,879 | | |
Property and equipment with undepreciated cost pledge as collateral for long term debt | | | 298,100,000 | | | |
Excess net worth calculated under covenants in the Notes, the Bonds, and the Line | | | 222,400,000 | | | |
Interest Rate Swap Two [Member] | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Derivative notional amount | | | $ 146,000,000 | | | |
Derivative, fixed interest rate | | | 2.95% | | | |
Interest Rate Swap Two [Member] | One-Month LIBOR [Member] | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt instrument variable interest rate | | | 1.50% | | | |
Interest Rate Swap [Member] | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Derivative notional amount | | | $ 41,000,000 | | | |
Derivative, fixed interest rate | | | 3.92% | | | |
Other comprehensive income, net of income taxes | | | $ 2,100,000 | $ 2,200,000 | | |
Unrealized losses on cash flow hedge | | | $ (10,800,000) | | | |
Interest Rate Swap [Member] | One-Month LIBOR [Member] | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt instrument variable interest rate | | | 1.65% | | | |
Senior Notes, Interest Rate of 5.75%, Maturing 2023 [Member] | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt instrument principal amount | | | | | $ 700,000,000 | |
Debt instrument, redemption price as percentage of principal amount | | | | 101.917% | | |
Maturity period of senior notes | | | 2023 | | | |
Debt instrument stated interest rate | | | | | 5.75% | |
Debt instrument outstanding balance | | | $ 295,000,000 | | | |
Senior Notes, Interest Rate of 5.75%, Maturing 2023 [Member] | Notes Redeemed on July 9, 2020 [Member] | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt redemeed amount | | | $ 150,000,000 | | | |
Debt instrument, redemption price as percentage of principal amount | | | 100.958% | | | |
Senior Notes, Interest Rate of 5.75%, Maturing 2023 [Member] | Notes Redeemed on August 27, 2020 [Member] | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt redemeed amount | | $ 100,000,000 | | | | |
Debt instrument, redemption price as percentage of principal amount | | 100.958% | | | | |
Secured Debt [Member] | Interest Rate Swap Two [Member] | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Monthly principal amortization | | | $ 650,000 | | | |
Secured Debt [Member] | Interest Rate Swap [Member] | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt maturity date | | | Oct. 1, 2027 | | | |
Monthly principal amortization | | | $ 500,000 | | | |
Facility Bonds [Member] | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt maturity date | | | Jan. 1, 2036 | | | |
Description of interest rate on bonds | | | The interest rate on the Bonds is equal to one-month LIBOR (adjusted monthly) plus a credit spread, adjusted to reflect the income tax exemption. | | | |
Debt instrument outstanding balance | | | $ 68,000,000 | | | $ 99,700,000 |
Credit Line [Member] | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Line of credit facility borrowing capacity | | | 175,000,000 | | | |
Borrowings outstanding | | | 25,000,000 | | | |
Credit Line [Member] | Unused Letters Of Credit [Member] | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Line of credit facility borrowing capacity | | | 20,000,000 | | | |
Unused letters of credit issued | | | $ 1,100,000 | | | |
Real Estate Loan (the “Loan”) [Member] | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt instrument principal amount | $ 155,000,000 | | | | | |
Debt instrument term | 10 years | | | | | |
Debt instrument, periodic principal payment | $ 650,000 | | | | | |
Debt maturity date | | | Jan. 31, 2030 | | | |
Real Estate Loan (the “Loan”) [Member] | Senior Notes, Interest Rate of 5.75%, Maturing 2023 [Member] | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt extinguishment costs | | | | $ 3,700,000 | | |