Summary of Significant Accounting Policies Properties and Depreciation and Amortization (Details)	12 Months Ended
	Dec. 31, 2017
Office and restaurant equipment | Minimum
Properties
Property, Plant and Equipment, Useful Life	3 years
Office and restaurant equipment | Maximum
Properties
Property, Plant and Equipment, Useful Life	20 years
Transportation equipment | Minimum
Properties
Property, Plant and Equipment, Useful Life	3 years
Transportation equipment | Maximum
Properties
Property, Plant and Equipment, Useful Life	15 years
Buildings and improvements | Minimum
Properties
Property, Plant and Equipment, Useful Life	7 years
Buildings and improvements | Maximum
Properties
Property, Plant and Equipment, Useful Life	30 years