{"cik":1564538,"taxonomy":"us-gaap","tag":"EarningsPerShareBasic","label":"Earnings Per Share, Basic","description":"The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.","entityName":"GRANITE REAL ESTATE INVESTMENT TRUST","units":{"CAD/shares":[{"start":"2010-01-01","end":"2010-12-31","val":-1.13,"accn":"0001047469-13-002226","fy":2012,"fp":"FY","form":"40-F","filed":"2013-03-06","frame":"CY2010"},{"start":"2011-01-01","end":"2011-12-31","val":3.25,"accn":"0001047469-13-002226","fy":2012,"fp":"FY","form":"40-F","filed":"2013-03-06","frame":"CY2011"},{"start":"2012-01-01","end":"2012-12-31","val":1.52,"accn":"0001047469-13-002226","fy":2012,"fp":"FY","form":"40-F","filed":"2013-03-06","frame":"CY2012"}]}}