Summary Of Significant Accounting Policies - Estimated Useful Lives Of Assets (Details)	12 Months Ended
	Dec. 31, 2019
Building
Property, Plant and Equipment [Line Items]
Useful Lives	30 years
Building improvements
Property, Plant and Equipment [Line Items]
Useful Lives	15 years
Equipment and furniture
Property, Plant and Equipment [Line Items]
Useful Lives	5 years
Operating lease assets | Maximum
Property, Plant and Equipment [Line Items]
Useful Lives	5 years
Operating lease assets | Minimum
Property, Plant and Equipment [Line Items]
Useful Lives	1 year
Computer and office equipment
Property, Plant and Equipment [Line Items]
Useful Lives	3 years
Enterprise-wide software
Property, Plant and Equipment [Line Items]
Useful Lives	5 years
Purchased software
Property, Plant and Equipment [Line Items]
Useful Lives	3 years