Investments - Summary of Remaining Weighted Average Amortization Period for Intangible Assets and Liabilities (Details)	12 Months Ended
	Dec. 31, 2018
Finite Lived Intangible Assets [Line Items]
Total intangible assets	10 years 2 months 12 days
Remaining weighted average amortization period, Intangible market lease liabilities	15 years 9 months 18 days
In-place Leases
Finite Lived Intangible Assets [Line Items]
Remaining weighted average amortization period, In-place leases	10 years 8 months 12 days
Intangible Market Lease Assets
Finite Lived Intangible Assets [Line Items]
Total intangible assets	8 years 9 months 18 days