XML 18 R33.htm IDEA: XBRL DOCUMENT v3.3.0.814
Retirement Benefits (Details) - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended
Sep. 25, 2015
Sep. 26, 2014
Sep. 25, 2015
Sep. 26, 2014
Pension        
Defined Benefit Plan Disclosure [Line Items]        
Service cost $ 2,265 $ 1,707 $ 6,268 $ 5,146
Interest cost 3,741 3,909 11,121 11,985
Expected return on assets (5,010) (5,311) (14,586) (15,941)
Amortization and other 2,291 1,341 7,070 4,029
Net periodic benefit cost 3,287 1,646 9,873 5,219
Postretirement Medical        
Defined Benefit Plan Disclosure [Line Items]        
Service cost 107 115 407 365
Interest cost 263 181 716 736
Amortization (63) (229) (265) (483)
Net periodic benefit cost $ 307 $ 67 $ 858 $ 618