The IAI 1125 Astra SPX was conducting an instrument flight rules flight from West Palm Beach, Florida, to Hamilton, Ontario, with two pilots on board. The co-pilot was seated in the left seat and was the pilot flying. Approaching the destination, the flight was cleared for the instrument landing system approach to runway 12 at the Hamilton Airport. The approach was at night in instrument meteorological conditions. At 400 to 500 feet above ground level, the flight crew saw the runway. At approximately 19:02 local time, the aircraft touched down on the wet runway with about 3000 feet of runway remaining. The flight crew used all available braking systems to slow the aircraft. However, it ran off the end of the runway and travelled 122 feet downslope before it came to an abrupt stop when the nosewheel sheared off. The aircraft sustained substantial damage, but neither flight crew member was injured during the runway excursion. Findings as to Causes and Contributing Factors 1. The pilot flying was slow to reduce the power to idle after flaring the aircraft for landing. Due to the excess airspeed and power, the aircraft floated, touching down with approximately 3000 feet of runway remaining. 2. Although the available 3000 feet of runway remaining exceeded the unfactored estimated ground roll of 2200 feet, the aircraft was unable to stop. A touchdown speed higher than the landing reference speed (Vref), slow deployment of the thrust reversers, standing water at the intersection of the runways, friction values at the runway ends that were at or below the Transport Canada runway maintenance planning level, and limited tire tread depth likely contributed to the runway excursion. 3. During the landing roll, the aircraft?s tires hydroplaned, reducing the braking forces.