Summary Of Significant Accounting Policies (Compensation Expense And Related Tax Benefit For Equity-Based Payments) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Summary Of Significant Accounting Policies [Line Items]
Total compensation expense	$ 13,107	$ 10,112	$ 9,989
Income tax benefit	4,522	3,489	3,446
Cost Of Sales [Member]
Summary Of Significant Accounting Policies [Line Items]
Total compensation expense	1,029	882	844
Selling And Marketing [Member]
Summary Of Significant Accounting Policies [Line Items]
Total compensation expense	1,463	1,368	1,404
Research And Development [Member]
Summary Of Significant Accounting Policies [Line Items]
Total compensation expense	1,387	1,282	1,426
General And Administrative [Member]
Summary Of Significant Accounting Policies [Line Items]
Total compensation expense	$ 9,228	$ 6,580	$ 6,315