Income Taxes - Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Federal, State and Local Tax [Member]
Reconciliation Of Unrecognized Tax Benefits [Line Items]
Beginning Balance	$ 24,537	$ 10,712	$ 14,611
Increases as a result of tax positions taken during the period	12,237	8,108	769
Decreases as a result of settlements with taxing authorities		(1,515)	(4,668)
Unrealized tax benefits acquired in a business combination		7,232
Decreases as a result of tax positions taken in prior years	(885)
Ending Balance	35,889	24,537	10,712
Accrued Interest [Member]
Reconciliation Of Unrecognized Tax Benefits [Line Items]
Beginning Balance	7,969	3,869	14,696
Increases as a result of tax positions taken in prior years	656	807	453
Decreases as a result of settlements with taxing authorities		(274)	(11,280)
Unrealized tax benefits acquired in a business combination		3,567
Decreases as a result of tax positions taken in prior years	(710)
Ending Balance	7,915	7,969	3,869
Unrecognized Income Tax Benefits [Member]
Reconciliation Of Unrecognized Tax Benefits [Line Items]
Beginning Balance	32,506	14,581	29,307
Increases as a result of tax positions taken during the period	12,237	8,108	769
Increases as a result of tax positions taken in prior years	656	807	453
Decreases as a result of settlements with taxing authorities		(1,789)	(15,948)
Unrealized tax benefits acquired in a business combination		10,799
Decreases as a result of tax positions taken in prior years	(1,595)
Ending Balance	43,804	$ 32,506	$ 14,581
Less: Federal, state and local income tax benefits	(15,332)
Net unrecognized tax benefits that, if recognized, would impact the effective income tax rate	$ 28,472