Idle time is the amount of time in seconds the Integration Service waits to receive messages before it stops reading from the source. -1 indicates an infinite period of time.
For example, if the idle time for a JMS session is 30 seconds, the Integration Service waits 30 seconds after reading from JMS. If no new messages arrive in JMS within 30 seconds, the Integration Service stops reading from JMS. It processes the messages and ends the session.