Income Taxes - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Deferred tax liability	$ 109	$ 0
Increase (decrease) in valuation allowance	35,200	17,700
Net operating loss carryforwards	152,100	354,200
Operating loss carryforwards, readily available		$ 278,000
New York State net operating loss carryforwards that expire	249,100
Federal net operating losses not subject to expiration	202,100
Limited federal net operating losses subject to expire	$ 55,100