Employee Benefits (Details) (USD $)	12 Months Ended
	Dec. 29, 2012		Dec. 31, 2011		Dec. 25, 2010
Change in fair value of plan assets [Roll Forward]
Payable maximum period to be considered current	12 months
Long-term liability	$ (35,187,000)		$ (32,839,000)
Percentage of gains and losses amortized over the average remaining service period (in hundredths)	10.00%
Weighted average assumptions in net periodic benefit calculations [Abstract]
Minimum annual assumed rate of increase in the per capita cost of covered benefits (in hundredths)	5.97%
Maximum annual assumed rate of increase in the per capita cost of covered benefits (in hundredths)	8.50%
Ultimate health care cost trend rate (in hundredths)	4.50%
Future expected benefit payments [Abstract]
Number of days notice needed to redeem monthly funding from investments in limited partnerships	30 days
One percent change assumptions [Abstract]
Increase in the accumulated postretirement benefit obligation	1,700,000
Increase in the service and interest cost components of net periodic postretirement benefit costs	100,000
Decrease in the accumulated postretirement benefit obligation	1,400,000
Decrease in the service and interest cost components of net periodic postretirement benefit costs	100,000
Defined Benefit Plan Disclosure [Line Items]
Plan assets	160,980,000		147,502,000
Approximate percentage of common stock invested in major industry (in hundredths)	90.00%		88.00%
Approximate percentage of mutual funds actively managed (in hundredths)	32.00%		30.00%
Approximate percentage of indexed mutual funds	68.00%		70.00%
Percentage of mutual funds' assets that are invested in U.S equities (in hundredths)	31.00%		32.00%
Percent of mutual funds' assets that are invested in non-U.S. equities (in hundredths)	59.00%		57.00%
Percent of mutual funds' assets that are invested in non-U.S. fixed income securities (in hundredths)	10.00%		11.00%
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Number of funds that can be redeemed quarterly	1
Number of funds that can be redeemed quarterly	1
Number of days notice needed to redeem quarterly funding from investments in limited partnerships	60 days
I.A.M Plan Trusts [Abstract]
Number of collective bargaining agreements	2
Pension contributions under the I.A.M. pension plan trusts	1,000,000		900,000		700,000
Percentage of employer contributions (in hundredths)	Less than 5.00%
Maximum percentage funded in the red zone, under the Pension Protection act of 2006 (in hundredths)	65.00%
Maximum percentage funded in the yellow zone, under the Pension Protection act of 2006 (in hundredths)	80.00%
Minimum percentage funded in the green zone, under the Pension Protection act of 2006 (in hundredths)	80.00%
Compensation expense for the Company's matching contribution	2,900,000		3,000,000		2,500,000
Contributions to UMWA 1992 Benefit Plan	315,000		338,000		478,000
Limited partnerships [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	11,145,000
Purchases	314,000
Redemptions	(7,468,000)
Net appreciation in fair value	502,000
Ending balance	4,493,000
Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets	100,792,000		89,259,000
Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets	55,695,000		47,098,000
Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets	4,493,000		11,145,000
Fixed Income Securities [Member]
Target allocation percentage [Abstract]
Company's target allocation (in hundredths)	25.00%
Cash And Money Market Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets	13,691,000		11,707,000
Cash And Money Market Funds [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets	13,691,000		11,707,000
Cash And Money Market Funds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets	0		0
Cash And Money Market Funds [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets	0		0
Alternative Investments [Member]
Target allocation percentage [Abstract]
Company's target allocation (in hundredths)	20.00%
Common stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets	65,604,000	[1]	58,498,000	[2]
Common stock [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets	65,604,000	[1]	58,498,000	[2]
Common stock [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets	0	[1]	0	[2]
Common stock [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets	0	[1]	0	[2]
Mutual funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets	77,192,000	[3]	66,152,000	[4]
Mutual funds [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets	21,497,000	[3]	19,054,000	[4]
Mutual funds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets	55,695,000	[3]	47,098,000	[4]
Mutual funds [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets	0	[3]	0	[4]
Limited partnerships [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets	4,493,000		11,145,000
Limited partnerships [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets	0		0
Limited partnerships [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets	0		0
Limited partnerships [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets	4,493,000		11,145,000
Pension Benefits [Member]
Change in benefit obligation [Roll Forward]
Obligation at beginning of year	180,341,000		174,464,000
Service cost	884,000		1,394,000
Interest cost	8,472,000		9,051,000
Actuarial loss (gain)	14,458,000		6,077,000
Benefit payments	(10,583,000)		(10,942,000)
Foreign currency translation adjustment	2,595,000		297,000
Obligation at end of year	196,167,000		180,341,000		174,464,000
Change in fair value of plan assets [Roll Forward]
Fair value of plan assets at beginning of year	147,502,000		156,215,000
Actual return on plan assets	18,964,000		(1,306,000)
Employer contributions	3,216,000		3,094,000
Benefit payments	(10,583,000)		(10,942,000)
Foreign currency translation adjustment	1,881,000		441,000
Fair value of plan assets at end of year	160,980,000		147,502,000		156,215,000
Underfunded status at end of year	(35,187,000)		(32,839,000)
Unrecognized net actuarial loss (gain)	61,125,000		58,436,000
Unrecognized prior service cost	2,000		3,000
Current liability	0		0
Long-term liability	(35,187,000)		(32,839,000)
Total underfunded status	(35,187,000)		(32,839,000)
Service cost	884,000		1,394,000		823,000
Interest cost	8,472,000		9,051,000		9,374,000
Expected return on plan assets	(10,263,000)		(11,569,000)		(11,443,000)
Amortization of prior service (credit) cost	1,000		2,000		294,000
Amortization of net loss (gain)	3,883,000		2,346,000		2,307,000
Net periodic benefit cost	2,977,000		1,224,000		1,355,000
Weighted average assumptions in benefit obligations calculations [Abstract]
Discount rate (in hundredths)	4.13%		4.80%
Expected long-term return on plan assets (in hundredths)	7.15%		7.11%
Rate of inflation (in hundredths)	2.70%		3.00%
Weighted average assumptions in net periodic benefit calculations [Abstract]
Discount rate (in hundredths)	4.80%		5.25%		5.77%
Expected long-term return on plan assets (in hundredths)	7.11%		7.51%		8.04%
Rate of inflation (in hundredths)	3.00%		3.40%		3.75%
Asset category [Abstract]
Total plan assets (in hundredths)	100.00%		100.00%
Future expected benefit payments [Abstract]
2013	11,079,000
2014	11,201,000
2015	11,352,000
2016	11,486,000
2017	11,620,000
2018-2022	59,548,000
Total	116,286,000
Company's expected contribution to benefit plans in next fiscal year	1,600,000
Pension Benefits [Member] | Equity Securities [Member]
Asset category [Abstract]
Total plan assets (in hundredths)	84.00%		80.00%
Target allocation percentage [Abstract]
Company's target allocation (in hundredths)	60.00%
Pension Benefits [Member] | Fixed Income Securities [Member]
Asset category [Abstract]
Total plan assets (in hundredths)	5.00%		5.00%
Pension Benefits [Member] | Cash And Money Market Funds [Member]
Asset category [Abstract]
Total plan assets (in hundredths)	9.00%		8.00%
Pension Benefits [Member] | Alternative Investments [Member]
Asset category [Abstract]
Total plan assets (in hundredths)	2.00%		7.00%
Other Benefits [Member]
Change in benefit obligation [Roll Forward]
Obligation at beginning of year	19,945,000		21,083,000
Service cost	380,000		344,000
Interest cost	635,000		993,000
Actuarial loss (gain)	(1,838,000)		(1,369,000)
Benefit payments	(1,131,000)		(937,000)
Foreign currency translation adjustment	105,000		(169,000)
Obligation at end of year	18,096,000		19,945,000		21,083,000
Change in fair value of plan assets [Roll Forward]
Fair value of plan assets at beginning of year	0		0
Actual return on plan assets	0		0
Employer contributions	1,131,000		937,000
Benefit payments	(1,131,000)		(937,000)
Foreign currency translation adjustment	0		0
Fair value of plan assets at end of year	0		0		0
Underfunded status at end of year	(18,096,000)		(19,945,000)
Unrecognized net actuarial loss (gain)	(1,630,000)		118,000
Unrecognized prior service cost	19,000		17,000
Current liability	(1,187,000)		(1,333,000)
Long-term liability	(16,909,000)		(18,612,000)
Total underfunded status	(18,096,000)		(19,945,000)
Service cost	380,000		344,000		273,000
Interest cost	635,000		993,000		1,333,000
Amortization of prior service (credit) cost	(2,000)		(3,000)		1,000
Amortization of net loss (gain)	(73,000)		(2,000)		156,000
Effect of curtailments and settlements	0		0		25,000
Net periodic benefit cost	940,000		1,332,000		1,788,000
Weighted average assumptions in benefit obligations calculations [Abstract]
Discount rate (in hundredths)	4.06%		4.97%
Rate of compensation increases (in hundredths)	5.04%		5.04%
Weighted average assumptions in net periodic benefit calculations [Abstract]
Discount rate (in hundredths)	4.97%		5.39%		6.08%
Rate of compensation increases (in hundredths)	5.04%		5.04%		5.04%
Future expected benefit payments [Abstract]
2013	1,187,000
2014	1,165,000
2015	1,232,000
2016	1,175,000
2017	1,178,000
2018-2022	6,192,000
Total	12,129,000
Company's expected contribution to benefit plans in next fiscal year	1,200,000
U.K Plan [Member]
Change in fair value of plan assets [Roll Forward]
Percent of above benefit obligation on company sponsored UK pension plan (in hundredths)	36.00%		36.00%
Percent above plan assets on company sponsored UK pension plan (in hundredths)	35.00%		33.00%
Defined benefit plan, amortization of net gains (losses)	$ 3,900,000

[1] Approximately 90 percent of common stock represents investments in U.S. companies primarily in the health care, utilities, financials, consumer staples, industrials, and information technology sectors. All investments in common stock are listed on U.S. stock exchanges.

[2] Approximately 88 percent of common stock represents investments in U.S. companies primarily in the health care, utilities, financials, consumer staples, industrials, information technology, and telecommunications sectors. All investments in common stock are listed on U.S. stock exchanges.

[3] Approximately 32 percent of mutual funds are actively managed funds and approximately 68 percent of mutual funds are index funds. Additionally, 31 percent of the mutual funds' assets are invested in U.S. equities, 59 percent in non-U.S. equities, and 10 percent in non-U.S. fixed income securities.

[4] Approximately 30 percent of mutual funds are actively managed funds and approximately 70 percent of mutual funds are index funds. Additionally, 32 percent of the mutual funds' assets are invested in U.S. equities, 57 percent in non-U.S. equities, and 11 percent in non-U.S. fixed income securities.