Summary of Significant Accounting Policies - Estimated Useful Lives of Assets (Details)	6 Months Ended
	Jun. 30, 2019
Building
Property Plant And Equipment [Line Items]
Buildings	27 years 6 months
Building improvements | Minimum
Property Plant And Equipment [Line Items]
Buildings	5 years
Building improvements | Maximum
Property Plant And Equipment [Line Items]
Buildings	27 years 6 months
Furniture, fixtures, and equipment | Minimum
Property Plant And Equipment [Line Items]
Buildings	3 years
Furniture, fixtures, and equipment | Maximum
Property Plant And Equipment [Line Items]
Buildings	5 years