Income Taxes - Additional Information (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018	Dec. 31, 2017
Valuation Allowance	$ 65.4	$ 62.1
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	35.00%
Tax Credit Carryforward, Valuation Allowance			$ 3.1
Deferred Income Tax Assets, Net			$ 3.1
Proceeds from Income Tax Refunds	$ 1.6
State and Local Jurisdiction [Member]
Operating Loss Carryforwards	$ 129.6
Operating Loss Carryforward Expiration Year	2037
Federal [Member]
Operating Loss Carryforwards	$ 245.4
Federal [Member] | Maximum [Member]
Operating Loss Carryforward Expiration Year	2037
New York State [Member]
Discontinued Operation, Tax Effect of Adjustment to Prior Period Gain (Loss) on Disposal	$ 31.1
New York City [Member]
Discontinued Operation, Tax Effect of Adjustment to Prior Period Gain (Loss) on Disposal	$ 25.5