Income Taxes - Reconciliation of Income Tax Rate (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Federal statutory rate (as a percent)	21.00%	35.00%	35.00%
State taxes, net of federal benefit (as a percent)	5.00%	2.90%	2.00%
Noncontrolling interest (as a percent)	(0.00%)	(13.70%)	(19.20%)
Tax credits (as a percent)	(1.80%)	(0.60%)	(0.60%)
Transaction costs (as a percent)	0.00%	1.40%	0.00%
Domestic production activities deduction	(0.00%)	(0.50%)	(1.10%)
Effect of Tax Cuts and Jobs Act (as a percent)	(0.00%)	(57.60%)	(0.00%)
Restricted share vesting	(1.00%)	(0.50%)	(0.00%)
Effect of deferred revaluation related to lower blended state tax rate	(2.00%)	(0.00%)	(0.00%)
Prior year return to provision adjustments	(2.80%)	(0.00%)	(0.00%)
Other (as a percent)	(0.10%)	1.50%	0.10%
Effective tax rate (as a percent)	18.30%	(32.10%)	16.20%