Significant Accounting Policies - Narrative (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Significant Accounting Policies [Abstract]
Revenue Recognized Under Net Reporting Arrangements	$ 39,299	$ 50,893	$ 56,528
Research and Development Expense	19,993	18,812	15,690
Accumulated Foreign Currency Translation Adjustments	3,336	4,709
Minimum Pension Liability	(46,914)	(34,260)
Unrealized Gain (Loss) on Available-For-Sale Securities	1,723	857
Fair Value of Derivative Instruments	0	(272)
Tax Amount Attributable to Change in Defined Benefit Plans	4,310	2,223	1,342
Tax Amount Attributable to Change in Fair Value of Derivatives	146	213	381
Tax Amount Attributable to Change in Available-for-sale Securities	446	(71)	128
Measurement of Tax Benefit, Minimum Likelihood of the Largest Amount Being Realized Upon Ultimate Settlement	50.00%
Customer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Provision for Doubtful Accounts	$ 1,254