Summary of Significant Accounting Policies (Details 2) (USD $)	12 Months Ended
	Dec. 31, 2012 item
Summary of Significant Accounting Policies
Number of businesses under which the entity is managed and operated	1
Stock split ratio for outstanding common stock	3
Stock dividend ratio upon stock split	2
Amount of maximum balance per bank account as insured by Federal Deposit Insurance Corporation	$ 250,000
Equipment | Minimum
Property and equipment
Estimated useful lives (in years)	2 years
Equipment | Maximum
Property and equipment
Estimated useful lives (in years)	3 years
Leasehold improvements
Property and equipment
Maximum amortization period of property and equipment	5 years
Leasehold improvements | Minimum
Property and equipment
Estimated useful lives (in years)	3 years
Leasehold improvements | Maximum
Property and equipment
Estimated useful lives (in years)	5 years
Furniture and fixtures | Minimum
Property and equipment
Estimated useful lives (in years)	5 years
Furniture and fixtures | Maximum
Property and equipment
Estimated useful lives (in years)	7 years
Buildings and building improvements | Maximum
Property and equipment
Estimated useful lives (in years)	39 years 6 months
Software and Software Development Cost | Minimum
Property and equipment
Estimated useful lives (in years)	5 years
Software and Software Development Cost | Maximum
Property and equipment
Estimated useful lives (in years)	10 years