Income Taxes - Reconciliation of Unrecognized Tax Benefits (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Liabilities for Unrecognized Tax Benefits at Beginning of Year	$ 4,400,000	$ 8,100,000	$ 5,100,000
Additions for Tax Positions of Current Year	0	700,000	3,100,000
Reductions for Tax Positions of Prior Years	(4,400,000)	(4,400,000)	0
Reduction for Expiration of Federal Statute of Limitations	0	0	(100,000)
Liabilities for Unrecognized Tax Benefits at End of Year	$ 0	$ 4,400,000	$ 8,100,000