Pension and Other Postretirement Benefits (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
U.S. Pension Benefits [Member]
Change in projected benefit obligations:
Projected benefit obligations, Beginning balance	$ 174,814	[1]	$ 153,595	[1]
Service cost	3,943	[1]	3,115	[1]	2,868
Interest cost	8,514	[1]	8,867	[1]	8,525
Plan amendments	(42)	[1]	153	[1]
Foreign currency exchange rate changes	0	[1]	0	[1]
Actuarial loss (gain)	17,289	[1]	16,121	[1]
Participant contributions	0	[1]	0	[1]
Benefits paid from plan assets	(7,425)	[1]	(6,992)	[1]
Benefits paid by the Corporation	(36)	[1]	(45)	[1]
Projected benefit obligations, Ending balance	197,057	[1]	174,814	[1]	153,595	[1]
Foreign Pension Benefits [Member]
Change in projected benefit obligations:
Projected benefit obligations, Beginning balance	50,698		47,009
Service cost	0		0		0
Interest cost	2,506		2,589		2,482
Plan amendments	0		0
Foreign currency exchange rate changes	2,434		(298)
Actuarial loss (gain)	5,239		2,321
Participant contributions	0		0
Benefits paid from plan assets	(1,667)		(923)
Benefits paid by the Corporation	0		0
Projected benefit obligations, Ending balance	59,210		50,698		47,009
Other Postretirement Benefits [Member]
Change in projected benefit obligations:
Projected benefit obligations, Beginning balance	22,348		17,058
Service cost	804		643		482
Interest cost	919		1,020		924
Plan amendments	0		0
Foreign currency exchange rate changes	0		0
Actuarial loss (gain)	(623)		4,277
Participant contributions	428		495
Benefits paid from plan assets	0		0
Benefits paid by the Corporation	(1,070)		(1,145)
Projected benefit obligations, Ending balance	$ 22,806		$ 22,348		$ 17,058

[1] Includes the non-qualified defined benefit pension plan.