Pension and Other Postretirement Benefits (Details 10) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
U.S. Pension Benefits [Member]
Net periodic pension and other postretirement costs
Service cost	$ 3,943	[1]	$ 3,115	[1]	$ 2,868
Interest cost	8,514	[1]	8,867	[1]	8,525
Expected return on plan assets	(9,556)		(9,658)		(9,572)
Amortization of prior service cost	668		656		656
Amortization of actuarial loss	6,087		4,236		3,484
Net cost	9,656		7,216		5,961
Foreign Pension Benefits [Member]
Net periodic pension and other postretirement costs
Service cost	0		0		0
Interest cost	2,506		2,589		2,482
Expected return on plan assets	(2,101)		(2,311)		(1,885)
Amortization of prior service cost	0		0		0
Amortization of actuarial loss	598		496		464
Net cost	1,003		774		1,061
Other Postretirement Benefits [Member]
Net periodic pension and other postretirement costs
Service cost	804		643		482
Interest cost	919		1,020		924
Expected return on plan assets	0		0		0
Amortization of prior service cost	85		86		86
Amortization of actuarial loss	71		256		140
Net cost	$ 1,879		$ 2,005		$ 1,632

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