How to avoid repeating a parameter definition in an Open API 2.0 spec?

openapi-spec.yaml

swagger: "2.0"
host: api.example.com
schemes:
  - https
info:
  title: An Example API Spec
  version: "1"

paths:
  /users/{user_id}/:
    get:
      operationId: getUser
      summary: Get user details
      parameters:
        - name: user_id
          in: path
          required: true
          type: string
      responses:
        "200":
          description: Success
    patch:
      operationId: updateUser
      summary: Update user details
      parameters:
        - name: user_id
          in: path
          required: true
          type: string
      responses:
        "204":
          description: Success
    delete:
      operationId: deleteUser
      summary: Delete a user
      parameters:
        - name: user_id
          in: path
          required: true
          type: string
      responses:
        "204":
          description: Success

parameters:
  userIdUrlParam:
    name: user_id
    in: path
    description: User ID
    required: true
    type: string

How to replace the three definitions of the parameter user_id with references to #/parameters/userIdUrlParam?