Income Taxes - Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Federal, State and Local Tax [Member]
Reconciliation Of Unrecognized Tax Benefits [Line Items]
Beginning Balance	$ 45,432	$ 35,889	$ 24,537
Increases as a result of tax positions taken during the period	13,426	13,019	12,237
Decreases as a result of settlements with taxing authorities	(664)	(332)
Decreases as a result of tax positions taken in prior years	(1,920)	(3,144)	(885)
Ending Balance	56,274	45,432	35,889
Accrued Interest [Member]
Reconciliation Of Unrecognized Tax Benefits [Line Items]
Beginning Balance	5,651	7,915	7,969
Increases as a result of tax positions taken in prior years	1,969	1,379	656
Decreases as a result of settlements with taxing authorities	(289)	(168)
Decreases as a result of tax positions taken in prior years	(702)	(3,475)	(710)
Ending Balance	6,629	5,651	7,915
Unrecognized Income Tax Benefits [Member]
Reconciliation Of Unrecognized Tax Benefits [Line Items]
Beginning Balance	51,083	43,804	32,506
Increases as a result of tax positions taken during the period	13,426	13,019	12,237
Increases as a result of tax positions taken in prior years	1,969	1,379	656
Decreases as a result of settlements with taxing authorities	(953)	(500)
Decreases as a result of tax positions taken in prior years	(2,622)	(6,619)	(1,595)
Ending Balance	62,903	$ 51,083	$ 43,804
Less: Federal, state and local income tax benefits	(13,209)
Net unrecognized tax benefits that, if recognized, would impact the effective income tax rate	$ 49,694