What’s a suburban office worth these days? A lot less than it used to be, at least in the case of one Class A office building in Basking Ridge, New Jersey. The value of the 135,000-square-foot building at 120 Mountain View Boulevard dropped 72 percent over the last decade, according to Morningstar. The four-story property was appraised at $7.7 million in July, down from $27 million in 2014.