Summary Of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2011

Summary Of Significant Accounting Policies [Abstract]

Advertising Costs

	Years Ended December 31,
	2011		2010		2009
Advertising Costs	$	42,728	$	37,941	$	32,242

Property And Equipment

Computer hardware	2 to 3 years
Computer software	2 to 5 years
Furniture and equipment	5 years
Leasehold improvements	Term of lease, 5 years maximum

Internal-Use Software

	Years Ended December 31,
	2011		2010		2009
Internal-use software development costs	$	18,133	$	10,512	$	16,655