Summary of Significant Accounting Policies - Property and Equipment, Goodwill and Other Intangible Assets (Details)	12 Months Ended
	Dec. 31, 2018
Land improvements
Estimated useful lives of property and equipment
Useful lives	15 years
Building and improvements | Minimum
Estimated useful lives of property and equipment
Useful lives	5 years
Building and improvements | Maximum
Estimated useful lives of property and equipment
Useful lives	31 years
Vessels | Minimum
Estimated useful lives of property and equipment
Useful lives	10 years
Vessels | Maximum
Estimated useful lives of property and equipment
Useful lives	35 years
Furniture, fixtures and equipment | Minimum
Estimated useful lives of property and equipment
Useful lives	3 years
Furniture, fixtures and equipment | Maximum
Estimated useful lives of property and equipment
Useful lives	31 years