Description of Operations and Summary of Significant Accounting Policies (Details 2) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011 Performance-contingent	Dec. 31, 2012 Equipment, furniture and fixtures Maximum	Dec. 31, 2012 Equipment, furniture and fixtures Minimum	Dec. 31, 2012 Software and computer equipment	Dec. 31, 2012 Capitalized software
Information related to useful life of property and equipment
Estimated useful life			7 years	5 years	3 years	3 years
Bonus Accruals
Timeframe for achievement of performance conditions		6 years
Deferred rent
Period over which average annual rent expense exceeded actual cash rent payments	1 year 6 months
Lease incentives	$ 2.6