stale element reference: element is not attached to the page document

What is the line which gives exception ??

The reason for this is because the element to which you have referred is removed from the DOM structure

I was facing the same problem while working with IEDriver. The reason was because javascript loaded the element one more time after i have referred so my date reference pointed to a nonexistent object even if it was right there in the UI. I used the following workaround:

try {
    WebElement date = driver.findElement(By.linkText(Utility.getSheetData(path, 7, 1, 2)));
    date.click();
}
catch(org.openqa.selenium.StaleElementReferenceException ex)
{
    WebElement date = driver.findElement(By.linkText(Utility.getSheetData(path, 7, 1, 2)));
    date.click();
}

See if the same can help you !