Income Taxes - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating Loss Carryforwards [Line Items]
Net operating losses	$ 61,800
Valuation allowance	(8,577)	$ (4,600)
Unrecognized tax benefits	54,899	$ 56,621	$ 53,752	$ 53,752
Unrecognized tax benefit from claims filed with IRS	53,700
KANSAS
Operating Loss Carryforwards [Line Items]
Income tax credits	12,800
Canada
Operating Loss Carryforwards [Line Items]
Net operating losses	27,600
OKLAHOMA
Operating Loss Carryforwards [Line Items]
Income tax credits	$ 5,500