According to Wikipedia, Jewish tradition divides the book of Tehilim into five sections (1-41, 42-72, 73-89, 90-106, 107-150). This is unsourced there; the references at the bottom of the page include The Jewish Study Bible (which I don't have) and a bunch of non-Jewish sources. I had not heard this idea before seeing a question about it on Biblical Hermeneutics, but Google tells me it's a commonly-held understanding at least among non-Jews.
Is this idea of Jewish origin? If so, what is the source, and what is the purpose of these divisions?