Fair Value Measurements (Fair value measurements on a recurring basis) (Details) - USD ($) $ in Thousands | Mar. 26, 2017 | Dec. 25, 2016 |
Fair value, inputs, level 1 [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets at fair value | $ 16,839 | $ 21,767 |
Liabilities at fair value | 0 | 0 |
Fair value, inputs, level 2 [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets at fair value | 0 | 0 |
Liabilities at fair value | 4,709 | 6,124 |
Reported value measurement [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets at fair value | 16,839 | 21,767 |
Liabilities at fair value | 4,709 | 6,124 |
Fair value, measurements, recurring [Member] | Fair value, inputs, level 1 [Member] | Accrued and other current liabilities [Member] | Interest rate swap [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Derivative liability, current | 0 | 0 |
Fair value, measurements, recurring [Member] | Fair value, inputs, level 1 [Member] | Accrued and other current liabilities [Member] | Commodity [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Derivative liability, current | 0 | 0 |
Fair value, measurements, recurring [Member] | Fair value, inputs, level 1 [Member] | Other long-term liabilities, net [Member] | Interest rate swap [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Derivative liability, noncurrent | 0 | 0 |
Fair value, measurements, recurring [Member] | Fair value, inputs, level 1 [Member] | Fixed income funds [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Cash and cash equivalents, fair value disclosure | 88 | 90 |
Restricted cash equivalents, fair value disclosure | 553 | 552 |
Fair value, measurements, recurring [Member] | Fair value, inputs, level 1 [Member] | Money market funds [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Cash and cash equivalents, fair value disclosure | 15,946 | 18,607 |
Restricted cash equivalents, fair value disclosure | 252 | 2,518 |
Fair value, measurements, recurring [Member] | Fair value, inputs, level 2 [Member] | Accrued and other current liabilities [Member] | Interest rate swap [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Derivative liability, current | 3,081 | 3,968 |
Fair value, measurements, recurring [Member] | Fair value, inputs, level 2 [Member] | Accrued and other current liabilities [Member] | Commodity [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Derivative liability, current | 171 | 157 |
Fair value, measurements, recurring [Member] | Fair value, inputs, level 2 [Member] | Other long-term liabilities, net [Member] | Interest rate swap [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Derivative liability, noncurrent | 1,457 | 1,999 |
Fair value, measurements, recurring [Member] | Fair value, inputs, level 2 [Member] | Fixed income funds [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Cash and cash equivalents, fair value disclosure | 0 | 0 |
Restricted cash equivalents, fair value disclosure | 0 | 0 |
Fair value, measurements, recurring [Member] | Fair value, inputs, level 2 [Member] | Money market funds [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Cash and cash equivalents, fair value disclosure | 0 | 0 |
Restricted cash equivalents, fair value disclosure | 0 | 0 |
Fair value, measurements, recurring [Member] | Reported value measurement [Member] | Accrued and other current liabilities [Member] | Interest rate swap [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Derivative liability, current | 3,081 | 3,968 |
Fair value, measurements, recurring [Member] | Reported value measurement [Member] | Accrued and other current liabilities [Member] | Commodity [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Derivative liability, current | 171 | 157 |
Fair value, measurements, recurring [Member] | Reported value measurement [Member] | Other long-term liabilities, net [Member] | Interest rate swap [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Derivative liability, noncurrent | 1,457 | 1,999 |
Fair value, measurements, recurring [Member] | Reported value measurement [Member] | Fixed income funds [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Cash and cash equivalents, fair value disclosure | 88 | 90 |
Restricted cash equivalents, fair value disclosure | 553 | 552 |
Fair value, measurements, recurring [Member] | Reported value measurement [Member] | Money market funds [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Cash and cash equivalents, fair value disclosure | 15,946 | 18,607 |
Restricted cash equivalents, fair value disclosure | $ 252 | $ 2,518 |