Commitments and Contingencies (Details) $ in Millions					6 Months Ended
	Jun. 07, 2019 item	Apr. 02, 2019 item	Nov. 21, 2018 item	Mar. 07, 2018 item	Jun. 30, 2019 USD ($) item	Apr. 30, 2019 item
Loss Contingencies [Line Items]
Letters of credit outstanding | $					$ 31.7
Remaining purchase obligation | $					$ 178.2
Telephone Consumer Protection Act Claim [Member]
Loss Contingencies [Line Items]
Number of proposed classes filing claims				2
Number of claims consolidated					3
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 claims dismissed					2
Number of officers		5	5
Number of underwriters			7
Federal Court Cases [Member]
Loss Contingencies [Line Items]
Number of claims						2
Number of claims dismissed					1
New York State Court Case [Member]
Loss Contingencies [Line Items]
Number of claims						1
Stockholder Derivative Action Filed In Nevada [Member]
Loss Contingencies [Line Items]
Number of officers	5
Number of board members	5