Significant Accounting Policies Significant Accounting Policies (Details)	Jun. 30, 2018
Accounting Policies [Abstract]
Variable Interest Entity Number Of Entities Not Primary Beneficiary	8

Number of Variable Interest Entities (VIE) or potential VIEs for which it is determined that the reporting entity is not the primary beneficiary.

No definition available.

Name:	nhi_VariableInterestEntityNumberOfEntitiesNotPrimaryBeneficiary
Namespace Prefix:	nhi_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant