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