Income Taxes - Deferred Tax Valuation Allowance (Details) - Valuation Allowance of Deferred Tax Assets - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Valuation Allowance [Line Items]
Beginning balance	$ 90,366	$ 59,349	$ 76,395
Additions based on changes in deferred tax assets	2,717	25,193	5,332
Increase (Reduction) in valuation allowance due to rate change from Tax Act		5,824	(22,378)
Reductions based on changes in deferred tax assets	(28,601)
Ending balance	$ 64,482	$ 90,366	$ 59,349