import re
rx = r"COMPANY DETAILS\s+Date\s*:.*\s*(.+)"
s = "COMPANY DETAILS\n\nDate : 01-06-2018\n\nABC Industries\n12-31 Lane\nNew York\n\nContact No. 1111"
m = re.search(rx, s, re.MULTILINE)
if m:
print(m.group(1))
aW1wb3J0IHJlCnJ4ID0gciJDT01QQU5ZIERFVEFJTFNccytEYXRlXHMqOi4qXHMqKC4rKSIKcyA9ICJDT01QQU5ZIERFVEFJTFNcblxuRGF0ZSA6IDAxLTA2LTIwMThcblxuQUJDIEluZHVzdHJpZXNcbjEyLTMxIExhbmVcbk5ldyBZb3JrXG5cbkNvbnRhY3QgTm8uIDExMTEiCm0gPSByZS5zZWFyY2gocngsIHMsIHJlLk1VTFRJTElORSkKaWYgbToKCXByaW50KG0uZ3JvdXAoMSkpCg==