Condensed Consolidated Statements Of Income Condensed Consolidated Statements of Income (Parenthetical) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Allocated Share-based Compensation Expense	$ 3,004	$ 2,384
Cost of Sales [Member]
Allocated Share-based Compensation Expense	83	154
Selling and Marketing Expense [Member]
Allocated Share-based Compensation Expense	584	491
Research and Development Expense [Member]
Allocated Share-based Compensation Expense	194	140
General and Administrative Expense [Member]
Allocated Share-based Compensation Expense	$ 2,143	$ 1,599