Supplemental Executive Retirement Plans - DC SERP (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Retirement Benefits [Abstract]
Estimated accumulated benefit obligation	$ 4.6	$ 4.5
Funded estimated accumulated benefit obligation	4.2	4.0
Unfunded estimated accumulated benefit obligation	$ 0.4	$ 0.5

The amount of unfunded estimated accumulated obligation benefit under the defined contribution plan.

No definition available.

Name:	hngr_DefinedContributionPlanEstimatedAccumulatedObligationBenefitUnfunded
Namespace Prefix:	hngr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant