Commitments and Contingencies (Details) $ in Millions	Jun. 30, 2026 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Employees under contract terminated by employer following a change in control	$ 30.9
Employees under contract terminated by employer without good cause or change in control	$ 11.7

Supplemental unemployment benefits for employees under contract that are terminated without good cause or the employee resigns for good reason in the absence of a change in control.

No definition available.

Name:	kfrc_SupplementalUnemploymentBenefitsOnNoChangeInControl
Namespace Prefix:	kfrc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant