Defined Benefit Pension Plans Schedule of Net Periodic Pension Benefit Costs (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 2,700	$ 2,512	$ 1,980
Interest cost	3,625	3,754	3,490
Expected Return on Plan Assets	(331)	(322)	(295)
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	68	74	3
Amortization of actuarial net (gains) loss	161	(85)	26
Defined Benefit Plan, Settlement and Other Benefit Costs	97	25	(80)
Net Periodic Benefit Cost	$ 6,320	$ 5,958	$ 5,124