Fair Value Measurements (Fair value measurements on a recurring basis) (Details) - Fair value, measurements, recurring [Member] - USD ($) $ in Thousands	Mar. 29, 2020	Dec. 29, 2019
Fair value, inputs, level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value disclosure	$ 9,370	$ 13,789
Liabilities, fair value disclosure	0	0
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 instruments - interest rate swaps, current liabilities	0	0
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 instruments - interest rate swaps, other long-term liabilities	0	0
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	2,324	1,037
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	7,046	12,752
Fair value, inputs, level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value disclosure	0	0
Liabilities, fair value disclosure	40,093	24,009
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 instruments - interest rate swaps, current liabilities	13,335	7,174
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 instruments - interest rate swaps, other long-term liabilities	26,758	16,835
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
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
Carrying value measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value disclosure	9,370	13,789
Liabilities, fair value disclosure	40,093	24,009
Carrying 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 instruments - interest rate swaps, current liabilities	13,335	7,174
Carrying 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 instruments - interest rate swaps, other long-term liabilities	26,758	16,835
Carrying 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	2,324	1,037
Carrying 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	$ 7,046	$ 12,752