Income Taxes - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
State tax effected net operating losses
TCJA tax benefit			$ 242,900
Effective tax rate	24.34%	20.21%	143.95%
Alternative minimum tax credits	$ 22,120	$ 114,149
Valuation allowance on deferred tax benefits related to equity method investments	31,763	14,943
Net reserve for unrecognized tax benefits related to alternative minimum tax	16,330	0	$ 0
Liability for accrued interest	3,100
Unrecognized tax benefits	520	$ 16,850	$ 663	$ 663
State
State tax effected net operating losses
Net operating loss carryforwards	390,100
Valuation allowance on operating loss carryforwards	$ 13,600
Excluding Impact of Tax Reform
State tax effected net operating losses
Effective tax rate	24.30%	21.80%	37.60%
Equity Method Investments
State tax effected net operating losses
Valuation allowance on deferred tax benefits related to equity method investments	$ 18,100