Income Taxes - Reconciliation (Detail)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Taxes
Income tax expense at U.S. federal statutory rate	21.00%	21.00%	35.00%
State and local income taxes, net of federal income tax benefit	4.39%	4.41%	3.25%
Impacts of enactment of tax reform		(0.51%)	(24.14%)
Federal tax credits	(4.38%)	(2.44%)	(2.31%)
Taxing authority audit settlements and other tax adjustments	(0.74%)	(3.85%)	0.03%
Tax impact of equity-based compensation transactions	(0.91%)	(0.54%)	(1.45%)
Tax impact of impairments	0.72%	0.03%	0.66%
Tax rate differential on foreign income	0.40%	0.43%	(0.55%)
Other	0.13%	0.51%	0.55%
Effective income tax rate	20.61%	19.04%	11.04%