Connections opened by Tomcat 9 exceeds the value of the maxIdle

I am currently developing a web application, using tomcat 9 and Postgres SQL 9.4, in the context.xml of the server conf folder create the following pool of connections.

<Resource name="jdbc/DBApp"
  factory="org.apache.tomcat.jdbc.pool.DataSourceFactory"
  auth="Container"
  type="javax.sql.DataSource"             
  username="xxx"
  password="xxx"
  driverClassName="org.postgresql.Driver"
  description="Base de datos de Eidyhealth"
  url="jdbc:postgresql://localhost:5432/APP"
  initialSize="5"
  maxActive="10"
  maxIdle="10"
  minIdle="5"
  suspectTimeout="60"
  maxWait="60000"
  timeBetweenEvictionRunsMillis="30000"
  minEvictableIdleTimeMillis="60000" 
  rollbackOnReturn="true"/>

However, when I start the tomcat and check the open connections in Postgres, I see 26 connections in the Idle state and when I run the application, the number goes up to 34.

What is the appropriate configuration in Tomcat 9 to ensure that only a maximum of 20 connections are created in the Postgres?

Thank you.