Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Taxes
Statutory U.S. federal income tax rate	21.00%	21.00%	35.00%
State income taxes, net of federal tax benefit	2.40%	4.00%	3.20%
State tax credits, net of federal effect	(1.00%)	(1.00%)	(0.70%)
Excess tax benefits	(2.30%)	(3.70%)	(5.80%)
Deferred tax revaluation (Federal Rate change)			(3.70%)
Nondeductible expenses	0.10%	0.40%
Other	(1.80%)	(0.50%)	0.30%
Effective Income Tax Rate Reconciliation, Percent, Total	18.40%	20.20%	28.30%