Equilibrium Constant and Pressure Change

For the reaction $2NO_2(g) \rightleftharpoons N_2O_4(g)$ at a constant temperature, a system is at equilibrium with partial pressures of $P_{NO_2}=0.50\,atm$ and $P_{N_2O_4}=0.10\,atm$. The corresponding equilibrium constant is $K_p=0.40$. If the volume of the container is reduced, causing the total pressure to double, what will be the value of $K_p$ after the system re-establishes equilibrium?