Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Allowance for doubtful accounts receivable	$ 1,108	$ 1,138
Common stock, par value per share	$ 0.01	$ 0.01
Common stock, shares authorized	190,000,000	190,000,000
Common stock, shares outstanding	90,320,306	89,914,113
Mack-Cali Realty LP [Member]
Allowance for doubtful accounts receivable	$ 1,108	$ 1,138
General partner common units outstanding	90,320,306	89,914,113
Limited partners common units outstanding	10,174,285	10,438,855