Employee benefit plans (Details) (USD $) | 12 Months Ended |
Dec. 27, 2013 | Dec. 28, 2012 |
Accumulated other comprehensive income for defined benefit plans [Abstract] | ' | | ' | |
Pension cost expected to be amortized from accumulated other comprehensive income | $100,000 | | ' | |
Benefit obligations in excess of plan assets [Abstract] | ' | | ' | |
Expected contributions to defined benefit plans in next fiscal year | 1,100,000 | | ' | |
Defined benefit plan expected future benefit payments | 2,100,000 | | ' | |
Expected benefit payments [Abstract] | ' | | ' | |
Defined contribution pension plan expense of non-U.S. subsidiaries | 1,100,000 | | 1,100,000 | |
Contribution expense under 401(k) plans | 700,000 | | 900,000 | |
Pension Plans [Member] | ' | | ' | |
Net pension cost related to defined benefit plans [Abstract] | ' | | ' | |
Service cost | 19,000 | | 0 | |
Interest cost | 1,616,000 | | 1,685,000 | |
Expected return on plan assets | -1,692,000 | | -1,615,000 | |
Amortization of transition obligation | 0 | | 5,000 | |
Amortization of prior service costs | 0 | | 1,000 | |
Recognized actuarial losses (gains) | 14,000 | | 0 | |
Curtailment gains | -16,000 | | -18,000 | |
Net periodic pension cost (income) | -59,000 | | 58,000 | |
Change in benefit obligation [Rollforward] | ' | | ' | |
Projected benefit obligation at beginning of year | 40,636,000 | | 38,195,000 | |
Service cost | 19,000 | | 0 | |
Interest cost | 1,616,000 | | 1,685,000 | |
Actuarial (gains) losses | -3,280,000 | | 2,969,000 | |
Benefits paid | -2,056,000 | | -2,152,000 | |
Plan curtailments | -16,000 | | -61,000 | |
Projected benefit obligation at end of year | 36,919,000 | | 40,636,000 | |
Change in fair value of plan assets [Rollforward] | ' | | ' | |
Fair value of plan assets at beginning of year | 35,117,000 | | 33,569,000 | |
Actual return on plan assets | -1,644,000 | | 3,592,000 | |
Employer contributions | 123,000 | | 108,000 | |
Benefits paid | -2,056,000 | | -2,152,000 | |
Fair value of plan assets at end of year | 31,540,000 | | 35,117,000 | |
Amounts recognized on the Consolidated Balance Sheets [Abstract] | ' | | ' | |
Non-current assets | 263,000 | | 235,000 | |
Non-current liabilities | -5,642,000 | | -5,754,000 | |
Net amount recorded | -5,379,000 | | -5,519,000 | |
Accumulated benefit obligation | 36,800,000 | | 40,200,000 | |
Accumulated other comprehensive income for defined benefit plans [Abstract] | ' | | ' | |
Actuarial losses | -4,065,000 | | -4,027,000 | |
Plan curtailment | -84,000 | | -84,000 | |
Amortization of prior service costs | -20,000 | | -20,000 | |
Amortization of transition obligations | -7,000 | | -7,000 | |
Accumulated other comprehensive income | -4,176,000 | | -4,138,000 | |
Benefit obligations in excess of plan assets [Abstract] | ' | | ' | |
Projected benefit obligation | 36,682,000 | | 40,477,000 | |
Accumulated benefit obligation | 36,760,000 | | 40,384,000 | |
Plan assets | 31,118,000 | | 34,723,000 | |
Asset category [Abstract] | ' | | ' | |
Weighted-average asset allocations, Total (in hundredths) | 100.00% | | 100.00% | |
Fair value of plan assets | 31,540,000 | | 35,117,000 | |
Assumptions used to develop defined benefit plan [Abstract] | ' | | ' | |
Discount rate (in hundredths) | 4.90% | | 4.10% | |
Expected long-term rates of return on plan assets (in hundredths) | 5.00% | | 5.00% | |
Expected benefit payments [Abstract] | ' | | ' | |
2014 | 2,140,000 | | ' | |
2015 | 2,115,000 | | ' | |
2016 | 2,189,000 | | ' | |
2017 | 2,206,000 | | ' | |
2018 | 2,235,000 | | ' | |
Thereafter | 26,034,000 | | ' | |
Total | 36,919,000 | | ' | |
PBGC [Member] | ' | | ' | |
Benefit obligations in excess of plan assets [Abstract] | ' | | ' | |
Expected contributions to defined benefit plans in next fiscal year | 1,000,000 | | ' | |
Future annual payments | ' | | 6,200,000 | |
Quoted Prices In Active Markets for Identical Assets (Level 1) [Member] | Pension Plans [Member] | ' | | ' | |
Change in fair value of plan assets [Rollforward] | ' | | ' | |
Fair value of plan assets at end of year | 31,500,000 | [1] | 35,100,000 | [1] |
Asset category [Abstract] | ' | | ' | |
Fair value of plan assets | 31,500,000 | [1] | 35,100,000 | [1] |
Significant Other Observable Inputs (Level 2) [Member] | Pension Plans [Member] | ' | | ' | |
Change in fair value of plan assets [Rollforward] | ' | | ' | |
Fair value of plan assets at end of year | 0 | [1] | 0 | [1] |
Asset category [Abstract] | ' | | ' | |
Fair value of plan assets | 0 | [1] | 0 | [1] |
Significant Unobservable Inputs (Level 3) [Member] | Pension Plans [Member] | ' | | ' | |
Change in fair value of plan assets [Rollforward] | ' | | ' | |
Fair value of plan assets at end of year | 0 | [1] | 0 | [1] |
Asset category [Abstract] | ' | | ' | |
Fair value of plan assets | 0 | [1] | 0 | [1] |
Equity Securities [Member] | Pension Plans [Member] | ' | | ' | |
Asset category [Abstract] | ' | | ' | |
Weighted-average asset allocations, Total (in hundredths) | 11.00% | | 11.00% | |
Fixed Income Securities [Member] | Pension Plans [Member] | ' | | ' | |
Asset category [Abstract] | ' | | ' | |
Weighted-average asset allocations, Total (in hundredths) | 87.00% | | 89.00% | |
Others [Member] | Pension Plans [Member] | ' | | ' | |
Asset category [Abstract] | ' | | ' | |
Weighted-average asset allocations, Total (in hundredths) | 2.00% | | 0.00% | |
Cash and Cash Equivalents [Member] | Pension Plans [Member] | ' | | ' | |
Change in fair value of plan assets [Rollforward] | ' | | ' | |
Fair value of plan assets at end of year | 100,000 | [1] | 100,000 | [1] |
Asset category [Abstract] | ' | | ' | |
Fair value of plan assets | 100,000 | [1] | 100,000 | [1] |
Cash and Cash Equivalents [Member] | Quoted Prices In Active Markets for Identical Assets (Level 1) [Member] | Pension Plans [Member] | ' | | ' | |
Change in fair value of plan assets [Rollforward] | ' | | ' | |
Fair value of plan assets at end of year | 100,000 | [1] | 100,000 | [1] |
Asset category [Abstract] | ' | | ' | |
Fair value of plan assets | 100,000 | [1] | 100,000 | [1] |
Cash and Cash Equivalents [Member] | Significant Other Observable Inputs (Level 2) [Member] | Pension Plans [Member] | ' | | ' | |
Change in fair value of plan assets [Rollforward] | ' | | ' | |
Fair value of plan assets at end of year | 0 | [1] | 0 | [1] |
Asset category [Abstract] | ' | | ' | |
Fair value of plan assets | 0 | [1] | 0 | [1] |
Cash and Cash Equivalents [Member] | Significant Unobservable Inputs (Level 3) [Member] | Pension Plans [Member] | ' | | ' | |
Change in fair value of plan assets [Rollforward] | ' | | ' | |
Fair value of plan assets at end of year | 0 | [1] | 0 | [1] |
Asset category [Abstract] | ' | | ' | |
Fair value of plan assets | 0 | [1] | 0 | [1] |
Fixed Income Securities Corporate Bonds [Member] | Pension Plans [Member] | ' | | ' | |
Change in fair value of plan assets [Rollforward] | ' | | ' | |
Fair value of plan assets at end of year | 27,500,000 | [1],[2] | 30,800,000 | [1],[2] |
Asset category [Abstract] | ' | | ' | |
Fair value of plan assets | 27,500,000 | [1],[2] | 30,800,000 | [1],[2] |
Fixed Income Securities Corporate Bonds [Member] | Quoted Prices In Active Markets for Identical Assets (Level 1) [Member] | Pension Plans [Member] | ' | | ' | |
Change in fair value of plan assets [Rollforward] | ' | | ' | |
Fair value of plan assets at end of year | 27,500,000 | [1],[2] | 30,800,000 | [1],[2] |
Asset category [Abstract] | ' | | ' | |
Fair value of plan assets | 27,500,000 | [1],[2] | 30,800,000 | [1],[2] |
Fixed Income Securities Corporate Bonds [Member] | Significant Other Observable Inputs (Level 2) [Member] | Pension Plans [Member] | ' | | ' | |
Change in fair value of plan assets [Rollforward] | ' | | ' | |
Fair value of plan assets at end of year | 0 | [1],[2] | 0 | [1],[2] |
Asset category [Abstract] | ' | | ' | |
Fair value of plan assets | 0 | [1],[2] | 0 | [1],[2] |
Fixed Income Securities Corporate Bonds [Member] | Significant Unobservable Inputs (Level 3) [Member] | Pension Plans [Member] | ' | | ' | |
Change in fair value of plan assets [Rollforward] | ' | | ' | |
Fair value of plan assets at end of year | 0 | [1],[2] | 0 | [1],[2] |
Asset category [Abstract] | ' | | ' | |
Fair value of plan assets | 0 | [1],[2] | 0 | [1],[2] |
Fixed Income Securities Short-term Debt Securities [Member] | Pension Plans [Member] | ' | | ' | |
Change in fair value of plan assets [Rollforward] | ' | | ' | |
Fair value of plan assets at end of year | 500,000 | [1],[3] | 500,000 | [1],[3] |
Asset category [Abstract] | ' | | ' | |
Fair value of plan assets | 500,000 | [1],[3] | 500,000 | [1],[3] |
Fixed Income Securities Short-term Debt Securities [Member] | Quoted Prices In Active Markets for Identical Assets (Level 1) [Member] | Pension Plans [Member] | ' | | ' | |
Change in fair value of plan assets [Rollforward] | ' | | ' | |
Fair value of plan assets at end of year | 500,000 | [1],[3] | 500,000 | [1],[3] |
Asset category [Abstract] | ' | | ' | |
Fair value of plan assets | 500,000 | [1],[3] | 500,000 | [1],[3] |
Fixed Income Securities Short-term Debt Securities [Member] | Significant Other Observable Inputs (Level 2) [Member] | Pension Plans [Member] | ' | | ' | |
Change in fair value of plan assets [Rollforward] | ' | | ' | |
Fair value of plan assets at end of year | 0 | [1],[3] | 0 | [1],[3] |
Asset category [Abstract] | ' | | ' | |
Fair value of plan assets | 0 | [1],[3] | 0 | [1],[3] |
Fixed Income Securities Short-term Debt Securities [Member] | Significant Unobservable Inputs (Level 3) [Member] | Pension Plans [Member] | ' | | ' | |
Change in fair value of plan assets [Rollforward] | ' | | ' | |
Fair value of plan assets at end of year | 0 | [1],[3] | 0 | [1],[3] |
Asset category [Abstract] | ' | | ' | |
Fair value of plan assets | 0 | [1],[3] | 0 | [1],[3] |
Equity Securities Domestic Small-cap Value [Member] | Pension Plans [Member] | ' | | ' | |
Change in fair value of plan assets [Rollforward] | ' | | ' | |
Fair value of plan assets at end of year | 1,000,000 | [1],[4] | 1,100,000 | [1],[4] |
Asset category [Abstract] | ' | | ' | |
Fair value of plan assets | 1,000,000 | [1],[4] | 1,100,000 | [1],[4] |
Equity Securities Domestic Small-cap Value [Member] | Quoted Prices In Active Markets for Identical Assets (Level 1) [Member] | Pension Plans [Member] | ' | | ' | |
Change in fair value of plan assets [Rollforward] | ' | | ' | |
Fair value of plan assets at end of year | 1,000,000 | [1],[4] | 1,100,000 | [1],[4] |
Asset category [Abstract] | ' | | ' | |
Fair value of plan assets | 1,000,000 | [1],[4] | 1,100,000 | [1],[4] |
Equity Securities Domestic Small-cap Value [Member] | Significant Other Observable Inputs (Level 2) [Member] | Pension Plans [Member] | ' | | ' | |
Change in fair value of plan assets [Rollforward] | ' | | ' | |
Fair value of plan assets at end of year | 0 | [1],[4] | 0 | [1],[4] |
Asset category [Abstract] | ' | | ' | |
Fair value of plan assets | 0 | [1],[4] | 0 | [1],[4] |
Equity Securities Domestic Small-cap Value [Member] | Significant Unobservable Inputs (Level 3) [Member] | Pension Plans [Member] | ' | | ' | |
Change in fair value of plan assets [Rollforward] | ' | | ' | |
Fair value of plan assets at end of year | 0 | [1],[4] | 0 | [1],[4] |
Asset category [Abstract] | ' | | ' | |
Fair value of plan assets | 0 | [1],[4] | 0 | [1],[4] |
Equity Securities Domestic Mid-cap Value [Member] | Pension Plans [Member] | ' | | ' | |
Change in fair value of plan assets [Rollforward] | ' | | ' | |
Fair value of plan assets at end of year | 1,900,000 | [1],[5] | 2,100,000 | [1],[5] |
Asset category [Abstract] | ' | | ' | |
Fair value of plan assets | 1,900,000 | [1],[5] | 2,100,000 | [1],[5] |
Equity Securities Domestic Mid-cap Value [Member] | Quoted Prices In Active Markets for Identical Assets (Level 1) [Member] | Pension Plans [Member] | ' | | ' | |
Change in fair value of plan assets [Rollforward] | ' | | ' | |
Fair value of plan assets at end of year | 1,900,000 | [1],[5] | 2,100,000 | [1],[5] |
Asset category [Abstract] | ' | | ' | |
Fair value of plan assets | 1,900,000 | [1],[5] | 2,100,000 | [1],[5] |
Equity Securities Domestic Mid-cap Value [Member] | Significant Other Observable Inputs (Level 2) [Member] | Pension Plans [Member] | ' | | ' | |
Change in fair value of plan assets [Rollforward] | ' | | ' | |
Fair value of plan assets at end of year | 0 | [1],[5] | 0 | [1],[5] |
Asset category [Abstract] | ' | | ' | |
Fair value of plan assets | 0 | [1],[5] | 0 | [1],[5] |
Equity Securities Domestic Mid-cap Value [Member] | Significant Unobservable Inputs (Level 3) [Member] | Pension Plans [Member] | ' | | ' | |
Change in fair value of plan assets [Rollforward] | ' | | ' | |
Fair value of plan assets at end of year | 0 | [1],[5] | 0 | [1],[5] |
Asset category [Abstract] | ' | | ' | |
Fair value of plan assets | 0 | [1],[5] | 0 | [1],[5] |
Equity Securities International Diversified Value [Member] | Pension Plans [Member] | ' | | ' | |
Change in fair value of plan assets [Rollforward] | ' | | ' | |
Fair value of plan assets at end of year | 500,000 | [1],[6] | 500,000 | [1],[6] |
Asset category [Abstract] | ' | | ' | |
Fair value of plan assets | 500,000 | [1],[6] | 500,000 | [1],[6] |
Equity Securities International Diversified Value [Member] | Quoted Prices In Active Markets for Identical Assets (Level 1) [Member] | Pension Plans [Member] | ' | | ' | |
Change in fair value of plan assets [Rollforward] | ' | | ' | |
Fair value of plan assets at end of year | 500,000 | [1],[6] | 500,000 | [1],[6] |
Asset category [Abstract] | ' | | ' | |
Fair value of plan assets | 500,000 | [1],[6] | 500,000 | [1],[6] |
Equity Securities International Diversified Value [Member] | Significant Other Observable Inputs (Level 2) [Member] | Pension Plans [Member] | ' | | ' | |
Change in fair value of plan assets [Rollforward] | ' | | ' | |
Fair value of plan assets at end of year | 0 | [1],[6] | 0 | [1],[6] |
Asset category [Abstract] | ' | | ' | |
Fair value of plan assets | 0 | [1],[6] | 0 | [1],[6] |
Equity Securities International Diversified Value [Member] | Significant Unobservable Inputs (Level 3) [Member] | Pension Plans [Member] | ' | | ' | |
Change in fair value of plan assets [Rollforward] | ' | | ' | |
Fair value of plan assets at end of year | 0 | [1],[6] | 0 | [1],[6] |
Asset category [Abstract] | ' | | ' | |
Fair value of plan assets | $0 | [1],[6] | $0 | [1],[6] |
|
[1] | See Note 15, Fair Value Measurements, for a description of the three levels within the fair value hierarchy. |
[2] | Debt securities that specialize in investment grade bonds of institutional investors and other treasury related securities. |
[3] | Generally, money market securities that maintain cash for interim purchases. |
[4] | Equity securities that focus on domestic public companies with low market capitalization. |
[5] | Equity securities that focus on domestic public companies with a mid-rated market capitalization. |
[6] | Equity securities that focus on international public companies but diversify their market capitalization to limit investment. |