Arelle 2015.02.01 for Mac was available to download from the developer's website when we last checked. We cannot confirm if there is a free download of this app available.
According to the results of the Google Safe Browsing check, the developer's site is safe. Despite this, we recommend checking the downloaded files with any free antivirus software. The program belongs to Developer Tools. The actual developer of this free software for Mac is arelle.
From the developer:
Arelle is a project to provide the XBRL community with an easy to use open source platform for XBRL. It supports XBRL and its extension features in an extensible manner. It does this in a compact yet robust framework that can be used as a desktop application and can be integrated with other applications and languages utilizing its web service. Arelle fully integrates test cases with the object models for XBRL instances and DTSes.
You may want to check out more Mac applications, such as Objective Basic, Pleinpot or PLCEdit, which might be related to Arelle.