وَجَآءُو عَلَىٰ قَمِيصِهِ بِدَمٍ كَذِبٍ ۚ قَالَ بَلْ سَوَّلَتْ لَكُمْ أَنفُسُكُمْ أَمْرًا ۖ فَصَبْرٌ جَمِيلٌ ۖ وَٱللَّهُ ٱلْمُسْتَعَانُ عَلَىٰ مَا تَصِفُونَ

The story of Joseph is definitely more detailed than what has been described in the Quran. But the real purpose of the Quran is to convey moral advice and not to engage in story telling. So, it deals with only those aspects that are useful for the purpose of giving moral lessons and omits other parts, leaving them for the historians to compile. According to traditions, Joseph was in the dry well for three days. During these three days, he was probably shown his future through dreams. In one of them, he saw himself coming out of the well and reaching a high position of honour and glory. Ultimately, such a wide gap develops between his position and the position of his brothers that they are unable to recognize him when they see him. All this was revealed by his dream. What Joseph’s brothers did was an act of extreme provocation. Unlike them, Joseph entrusted his fate to God and, sitting quietly in the dry well at a deserted place, waited for God’s help to arrive. Joseph’s father, Jacob, for his part, took the course of noble patience. According to some commentaries he is reported to have told his sons that had a wolf devoured Joseph, it would certainly have torn his shirt. He meant, what a noble wolf it was who took away Joseph and removed his blood-stained shirt to hand it over to them undamaged.

— Source: Tazkirul Quran (Maulana Wahiduddin Khan) via Quran.com (12:18)