Phosphatase that hydrolyzes imidodiphosphate, 3-phosphohistidine and 6-phospholysine. Has broad substrate specificity and can also hydrolyze inorganic diphosphate, but with lower efficiency (By similarity). diphosphate + H2O = H(+) + 2 phosphate Binds 1 Mg(2+) ion per subunit. Belongs to the HAD-like hydrolase superfamily.