The new taxonomy 2014-11-17 mandates Italian unlisted companies to codify in XBRL also the notes to the financial statements. Building on previous literature, the aim of this study is to analyze the impact of mandatory XBRL extension to the financial statements notes on financial reporting quality of the Italian unlisted companies. We focus our analysis on the taxonomy usage and the customizations made by the filers. Our data represents the very first sample of Italian financial statements filed in fully XBRL format. Despite the significant changes affecting the process of financial statement preparation, we find that Italian unlisted companies have accepted and acknowledged the potential benefits and limits of the new taxonomy. When dividing the notes section between textual blocks and tables, we find a clear preference for the filers to use textual blocks for both, standard and abbreviated financial statements. Overall, we find that filers of both financial statement types use extensively the customizations offered by the taxonomy. Moreover, for the filers of abbreviated financial statements, we show that they tend to use not only more table customizations but also tables that are proper for the standard financial statements, thus offering higher voluntary disclosure. [ABSTRACT FROM AUTHOR]