Investments - Summary of Remaining Weighted Average Amortization Period for Intangible Assets and Liabilities (Details)	3 Months Ended
	Mar. 31, 2019
Finite Lived Intangible Assets [Line Items]
Total intangible assets	10 years 1 month 6 days
Remaining weighted average amortization period, Intangible market lease liabilities	17 years 7 months 6 days
In-place Leases
Finite Lived Intangible Assets [Line Items]
Remaining weighted average amortization period, In-place leases	10 years 6 months
Intangible Market Lease Assets
Finite Lived Intangible Assets [Line Items]
Total intangible assets	8 years 10 months 24 days