Any comment to speed up the calculation of double-integral having Legendre polynomials?

Question

I want to compute the following double integral at $t=t_{0}$ rapidly. I tried different methods, but all are time consuming for I,J,M >7. Any comments to speed up the calculation??? $$\frac{1}{2}\int_{-1}^{1}\int_{-1}^{1}\left[ 1+\tanh(\lambda w(x,y,t)) \right]w(x,y,t)dxdy$$ where $$w(x,y,t)=W_{ijm}P_{i}(x)P_{j}(y)q_{m}(t)$$ $P_{j}(y)$ and $P_{i}(x)$ are Legendre polynomials and i, j and m are dummy indices where $i=0...I$, $j=0..J$ and $m=1..M$ which I,J and M are positive integers. $\lambda>1$, $W_{ijm}$ and $q_{m}(t_{0})$ are known parameters.