Income Taxes - Components of Benefit from Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Current
U.S. Federal	$ 0	$ (9,310)
State and local	0	(1,641)
Total current income tax benefit	0	(10,951)
Deferred
U.S. Federal	0	(576)
State and local	0	0
Total deferred income tax benefit	0	(576)
Total
U.S. Federal	0	(9,886)
State and local	0	(1,641)
Tax provision benefit	$ 0	$ (11,527)