若\(P\)是双曲线\(C： \dfrac {x^{2}}{a^{2}}- \dfrac {y^{2}}{b^{2}}=1(a,b > 0)\)在第一象限上一点，\(F _{1}\)，\(F _{2}\)为双曲线\(C\)的左、右焦点，\(|PF _{2} |=2b\)，\(Q( \dfrac {a}{2},0)\)到直线\(PF _{1}\)，\(PF _{2}\)距离相等，则双曲线\(C\)的离心率为\((\:\:\:\:)\)
A. \( \dfrac {5}{3}\)
B. \( \dfrac {3}{2}\) C. \( \dfrac {4}{3}\) D. \( \dfrac {5}{4}\)
