Real Estate (Classification of Investment Property Leases) (Details)	12 Months Ended
	Dec. 31, 2017 property
Lease classification:
Weighted average remaining lease term (years)	11 years 6 months
Operating
Lease classification:
Operating	2,791
Direct financing
Lease classification:
Direct financing	7
Building portion – direct financing / and portion – operating
Lease classification:
Building portion – direct financing / and portion – operating	2