Pensions and Other Post-retirement Benefits (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Change in plan assets
Fair value of plan assets at end of year	$ 163,436	$ 140,344
Pension Benefits [Member]
Change in benefit obligation
Benefit obligation at beginning of year	210,996	180,673
Service cost	7,915	6,955	5,135
Interest cost	9,912	9,786	9,156
Plan amendments	117	430
Actuarial loss	32,595	21,280
Benefit payments from fund	(7,523)	(7,512)
Benefit payments directly by Company	(129)	(127)
Expenses paid from assets	(293)	(479)
Medicare Part D subsidy	0	0
Foreign currency exchange rate changes	249	(10)
Benefit obligation at end of year	253,839	210,996	180,673
Change in plan assets
Fair value of plan assets at beginning of year	140,344	131,761
Actual return on plan assets	18,534	(5,215)
Employer contributions	12,218	21,706
Benefit payments from fund	(7,523)	(7,512)
Expenses paid from assets	(293)	(479)
Foreign currency exchange rate changes	156	83
Fair value of plan assets at end of year	163,436	140,344	131,761
Funded status at end of year	(90,403)	(70,652)
Amounts recognized in the Consolidated Balance Sheets consist of:
Other assets	1,112	0
Other liabilities and accrued items	(475)	0
Retirement and post-employment benefits	(91,040)	(70,652)
Amounts recognized in the consolidated balance sheets, total	(90,403)	(70,652)
Amounts recognized in other comprehensive income (before tax) consist of:
Net actuarial loss	127,027	106,583
Net prior service (credit) cost	(2,075)	(2,527)
Amounts recognized in other comprehensive income (before tax),total	124,952	104,056
Amortizations expected to be recognized during next fiscal year (before tax):
Amortization of net loss	7,731	5,605
Amortization of prior service credit	(341)	(335)
Amortizations expected to be recognized during next fiscal year (before tax),total	7,390	5,270
Additional information
Accumulated benefit obligation for all defined benefit pension plans	242,854	204,359
For defined benefit pension plans with benefit obligations in excess of plan assets:
Aggregate benefit obligation	249,075	206,800
Aggregate fair value of plan assets	157,560	135,505
For defined benefit pension plans with accumulated benefit obligations in excess of plan assets:
Aggregate accumulated benefit obligation	238,090	200,163
Aggregate fair value of plan assets	157,560	135,505
Other Benefits [Member]
Change in benefit obligation
Benefit obligation at beginning of year	33,209	32,374
Service cost	285	284	273
Interest cost	1,440	1,596	1,738
Plan amendments	0	0
Actuarial loss	1,493	1,419
Benefit payments from fund	0	0
Benefit payments directly by Company	(2,432)	(2,735)
Expenses paid from assets	0	0
Medicare Part D subsidy	299	271
Foreign currency exchange rate changes	0	0
Benefit obligation at end of year	34,294	33,209	32,374
Change in plan assets
Fair value of plan assets at beginning of year	0	0
Actual return on plan assets	0	0
Employer contributions	0	0
Benefit payments from fund	0	0
Expenses paid from assets	0	0
Foreign currency exchange rate changes	0	0
Fair value of plan assets at end of year	0	0	0
Funded status at end of year	(34,294)	(33,209)
Amounts recognized in the Consolidated Balance Sheets consist of:
Other assets	0	0
Other liabilities and accrued items	(2,663)	(2,788)
Retirement and post-employment benefits	(31,631)	(30,421)
Amounts recognized in the consolidated balance sheets, total	(34,294)	(33,209)
Amounts recognized in other comprehensive income (before tax) consist of:
Net actuarial loss	2,472	978
Net prior service (credit) cost	115	202
Amounts recognized in other comprehensive income (before tax),total	2,587	1,180
Amortizations expected to be recognized during next fiscal year (before tax):
Amortization of net loss	0	0
Amortization of prior service credit	115	87
Amortizations expected to be recognized during next fiscal year (before tax),total	115	87
Additional information
Accumulated benefit obligation for all defined benefit pension plans	0	0
For defined benefit pension plans with benefit obligations in excess of plan assets:
Aggregate benefit obligation	0	0
Aggregate fair value of plan assets	0	0
For defined benefit pension plans with accumulated benefit obligations in excess of plan assets:
Aggregate accumulated benefit obligation	0	0
Aggregate fair value of plan assets	$ 0	$ 0