Pension, Postretirement and Postemployment Benefits, Beginning of Fair Value Measurement (Details) - USD ($) $ in Thousands	Dec. 27, 2015	Dec. 28, 2014
Fair values of plan assets by asset class and fair value hierarchy level [Abstract]
Fair Value of Plan Asset	$ 259,300	$ 272,000
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair values of plan assets by asset class and fair value hierarchy level [Abstract]
Fair Value of Plan Asset	51,900	32,100
Significant Other Observable Inputs (Level 2) [Member]
Fair values of plan assets by asset class and fair value hierarchy level [Abstract]
Fair Value of Plan Asset	204,900	181,500
Significant Unobservable Inputs (Level 3) [Member]
Fair values of plan assets by asset class and fair value hierarchy level [Abstract]
Fair Value of Plan Asset	2,500	58,400
Equity - Large Cap [Member]
Fair values of plan assets by asset class and fair value hierarchy level [Abstract]
Fair Value of Plan Asset	27,600	14,100
Equity - Large Cap [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair values of plan assets by asset class and fair value hierarchy level [Abstract]
Fair Value of Plan Asset	27,600	14,100
Equity - Large Cap [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair values of plan assets by asset class and fair value hierarchy level [Abstract]
Fair Value of Plan Asset	0	0
Equity - Large Cap [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair values of plan assets by asset class and fair value hierarchy level [Abstract]
Fair Value of Plan Asset	0	0
Equity - Small Cap [Member]
Fair values of plan assets by asset class and fair value hierarchy level [Abstract]
Fair Value of Plan Asset	24,300	18,000
Equity - Small Cap [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair values of plan assets by asset class and fair value hierarchy level [Abstract]
Fair Value of Plan Asset	24,300	18,000
Equity - Small Cap [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair values of plan assets by asset class and fair value hierarchy level [Abstract]
Fair Value of Plan Asset	0	0
Equity - Small Cap [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair values of plan assets by asset class and fair value hierarchy level [Abstract]
Fair Value of Plan Asset	0	0
Equity - International [Member]
Fair values of plan assets by asset class and fair value hierarchy level [Abstract]
Fair Value of Plan Asset	37,500	34,300
Equity - International [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair values of plan assets by asset class and fair value hierarchy level [Abstract]
Fair Value of Plan Asset	0	0
Equity - International [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair values of plan assets by asset class and fair value hierarchy level [Abstract]
Fair Value of Plan Asset	37,500	34,300
Equity - International [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair values of plan assets by asset class and fair value hierarchy level [Abstract]
Fair Value of Plan Asset	0	0
Equity - Other [Member]
Fair values of plan assets by asset class and fair value hierarchy level [Abstract]
Fair Value of Plan Asset	2,500	36,400
Equity - Other [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair values of plan assets by asset class and fair value hierarchy level [Abstract]
Fair Value of Plan Asset	0	0
Equity - Other [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair values of plan assets by asset class and fair value hierarchy level [Abstract]
Fair Value of Plan Asset	0	0
Equity - Other [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair values of plan assets by asset class and fair value hierarchy level [Abstract]
Fair Value of Plan Asset	2,500	36,400
Fixed Income Funds [Member]
Fair values of plan assets by asset class and fair value hierarchy level [Abstract]
Fair Value of Plan Asset	122,600	132,100
Fixed Income Funds [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair values of plan assets by asset class and fair value hierarchy level [Abstract]
Fair Value of Plan Asset	0	0
Fixed Income Funds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair values of plan assets by asset class and fair value hierarchy level [Abstract]
Fair Value of Plan Asset	122,600	110,100
Fixed Income Funds [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair values of plan assets by asset class and fair value hierarchy level [Abstract]
Fair Value of Plan Asset	0	22,000
Total Return Fund [Member]
Fair values of plan assets by asset class and fair value hierarchy level [Abstract]
Fair Value of Plan Asset	27,700	28,600
Total Return Fund [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair values of plan assets by asset class and fair value hierarchy level [Abstract]
Fair Value of Plan Asset	0	0
Total Return Fund [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair values of plan assets by asset class and fair value hierarchy level [Abstract]
Fair Value of Plan Asset	27,700	28,600
Total Return Fund [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair values of plan assets by asset class and fair value hierarchy level [Abstract]
Fair Value of Plan Asset	0	0
Cash Equivalents [Member]
Fair values of plan assets by asset class and fair value hierarchy level [Abstract]
Fair Value of Plan Asset	17,100	8,500
Cash Equivalents [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair values of plan assets by asset class and fair value hierarchy level [Abstract]
Fair Value of Plan Asset	0	0
Cash Equivalents [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair values of plan assets by asset class and fair value hierarchy level [Abstract]
Fair Value of Plan Asset	17,100	8,500
Cash Equivalents [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair values of plan assets by asset class and fair value hierarchy level [Abstract]
Fair Value of Plan Asset	$ 0	$ 0