Summary of Significant Accounting Policies (Details 3)	12 Months Ended
	Dec. 31, 2011 reportingunit
Goodwill
Number of reporting units for goodwill impairment test	2
Computer equipment and software
Property and equipment
Useful life, minimum (in years)	3
Useful life, maximum (in years)	5
Furniture and fixtures
Property and equipment
Useful life, minimum (in years)	3
Useful life, maximum (in years)	5
Telephone system
Property and equipment
Useful life, minimum (in years)	3
Useful life, maximum (in years)	5