Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Accounts receivable, allowance	$ 284	$ 1,653
Accrued rent receivable, allowance	$ 11,009	$ 11,266
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	400,000,000	400,000,000
Common stock, shares issued and outstanding (in shares)	176,194,918	176,873,324
Common shares in grantor trust, issued and outstanding (in shares)	1,105,542	977,120
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Accounts receivable, allowance	$ 284	$ 1,653
Accrued rent receivable, allowance	$ 11,009	$ 11,266
Redeemable limited partnership units issued and outstanding (in units)	981,626	982,871
General partners' capital account, units issued and outstanding (in units)	176,194,918	176,873,324