Commitments and Contingencies (Details) $ in Millions					1 Months Ended	12 Months Ended
	Oct. 08, 2019 item	Jun. 07, 2019 item	Apr. 02, 2019 item	Nov. 21, 2018 item	Apr. 30, 2019 item	Dec. 31, 2019 USD ($) item
Loss Contingencies [Line Items]
Letters of credit outstanding | $						$ 32.7
Obligation in 2020 | $						$ 111.2
Stockholder Claims [Member]
Loss Contingencies [Line Items]
Number of claims					8
Tennessee State Court Cases [Member]
Loss Contingencies [Line Items]
Number of claims					5
Number of officers				5
Number of underwriters				7
Number of remaining claims						3
Federal Court Cases [Member]
Loss Contingencies [Line Items]
Number of claims					2
Number of claims dismissed						1
Number of officers			5
Number of underwriters	7
New York State Court Case [Member]
Loss Contingencies [Line Items]
Number of claims					1
Number of claims dismissed						2
Stockholder Derivative Action Filed In Nevada [Member]
Loss Contingencies [Line Items]
Number of officers		5
Number of board members		5