TM4C1294NCPDT: RX time-out interrupt takes to trigger

I didn't find this information in the TM4C1294NCPDT datasheet. I'm just trying to better understand how long the UART RX timeout interrupt will take to trigger after communications stop. Is it configurable?

Is there any expression to provide some numbers for it? Based on system clock, UART baud rate or some multiple of UART frame time?

Thanks,
Richard