Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
postĭdĕa, adv., ante-class. lengthened form for postea, after that, afterwards: nunc quo profectus sum, ibo, postidea domum me recipiam, Plaut. Aul. 1, 2, 40; id. Stich. 1, 2, 40; id. Truc. 2, 4, 67.
With loci, afterwards: postidea loci, Qui deliquit, vapulabit, Plaut. Cist. Grex. 3; id. Stich. 5, 5, 17.