Summary of Significant Accounting Policies - Property and Equipment (Details)	12 Months Ended
	Dec. 31, 2017
Vehicles [Member] | Minimum
Property, Plant and Equipment [Line Items]
Useful life of property and equipment (in years)	5 years
Vehicles [Member] | Maximum
Property, Plant and Equipment [Line Items]
Useful life of property and equipment (in years)	10 years
Furniture, fixtures and equipment [Member] | Minimum
Property, Plant and Equipment [Line Items]
Useful life of property and equipment (in years)	5 years
Furniture, fixtures and equipment [Member] | Maximum
Property, Plant and Equipment [Line Items]
Useful life of property and equipment (in years)	10 years
Land Improvements [Member] | Minimum
Property, Plant and Equipment [Line Items]
Useful life of property and equipment (in years)	5 years
Land Improvements [Member] | Maximum
Property, Plant and Equipment [Line Items]
Useful life of property and equipment (in years)	20 years
Building Improvements [Member] | Minimum
Property, Plant and Equipment [Line Items]
Useful life of property and equipment (in years)	5 years
Building Improvements [Member] | Maximum
Property, Plant and Equipment [Line Items]
Useful life of property and equipment (in years)	40 years
Building [Member]
Property, Plant and Equipment [Line Items]
Useful life of property and equipment (in years)	40 years