Interest and Other Income (Loss), net - Schedule Of Interest And Other Income (Loss), net (Parenthetical) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Schedule Of Investment Income Reported Amounts By Category [Line Items]
Preferred equity ownership percentage	24.40%
PGRESS Equity Holdings L.P. [Member]
Schedule Of Investment Income Reported Amounts By Category [Line Items]
Preferred equity investment income, attributable to parent	$ 890	$ 1,029	$ 1,393
Preferred equity ownership percentage	24.40%
PGRESS Equity Holdings L.P. [Member] | 2 Herald Square [Member]
Schedule Of Investment Income Reported Amounts By Category [Line Items]
Preferred equity ownership percentage		24.40%
Valuation allowance on preferred equity investment, attributable to parent		$ 4,780
Valuation allowance on preferred equity investment attributable to noncontrolling interests		$ 14,808