Real Estate (Classification of Investment Property Leases) (Details)	9 Months Ended
	Sep. 30, 2018 property option
Lease classification:
Weighted average remaining lease term (years)	11 years 5 months
Number of renewal options, or more | option	1
Operating
Lease classification:
Operating	2,861
Direct financing
Lease classification:
Direct financing	8
Building portion – direct financing/land portion – operating
Lease classification:
Building portion – direct financing/land portion – operating	1