Variable Interest Entities (Balances Related to Joint Ventures) (Details) $ in Millions	Sep. 30, 2017 USD ($)
Variable Interest Entity, Not Primary Beneficiary, Disclosures [Abstract]
Maximum Guarantee Exposure for Joint Venture Loans	$ 77.6

Maximum Guarantee Exposure for Joint Venture Loans

No definition available.

Name:	dre_MaximumGuaranteeExposureForJointVentureLoans
Namespace Prefix:	dre_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant