Contingencies (Details) $ in Millions		1 Months Ended		2 Months Ended	9 Months Ended
	Apr. 26, 2015	Jan. 31, 2010 USD ($)	Apr. 30, 1999 USD ($)	Jan. 31, 2020 numberOfStockholders	Sep. 30, 2020 child class lawsuit	Nov. 11, 2014 USD ($)	Jul. 26, 2013 USD ($)
Loss Contingencies [Line Items]
Number of stockholders who filed complaints | numberOfStockholders				2
Yellowstone
Loss Contingencies [Line Items]
Alleged loss of profits			$ 1.0
Unpaid accounts receivable			4.0
Alleged business investments			3.0
Initial estimate of loss of profits			$ 1.0
Court awarded damages from counterclaim		$ 4.0
Damages awarded, including attorney fees, inflation and interest							$ 17.0
Counter claim awarded, including inflation						$ 7.5	$ 7.5
Damages award including inflation and interest						$ 14.5
Fine on claims (as a percent)	1.00%
Sleeper
Loss Contingencies [Line Items]
Number of additional lawsuits pending | lawsuit					36
Number of children with injuries or fatalities related to lawsuits | child					40
Minimum | Sleeper
Loss Contingencies [Line Items]
Number of consumer classes | class					15