Condensed Consolidated Statements Of Income Condensed Consolidated Statements of Income (Parenthetical) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Allocated Share-based Compensation Expense	$ 2,425	$ 2,403	$ 7,108	$ 6,851
Cost of Sales [Member]
Allocated Share-based Compensation Expense	162	199	581	633
Selling and Marketing Expense [Member]
Allocated Share-based Compensation Expense	465	390	1,315	1,117
Research and Development Expense [Member]
Allocated Share-based Compensation Expense	103	111	311	344
General and Administrative Expense [Member]
Allocated Share-based Compensation Expense	$ 1,695	$ 1,703	$ 4,901	$ 4,757