Income Taxes - Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Federal, State and Local Tax [Member]
Reconciliation Of Unrecognized Tax Benefits [Line Items]
Beginning Balance	$ 10,712	$ 14,611	$ 16,548
Increases in unrecognized tax benefits as a result of tax positions taken during the period	8,108	769	2,267
Decreases in unrecognized tax benefits as a result of settlements with taxing authorities	(1,515)	(4,668)	(1,854)
Decreases in unrecognized tax benefits because applicable returns are no longer subject to examination			(2,350)
Unrealized tax benefits acquired in a business combination	7,232
Ending Balance	24,537	10,712	14,611
Accrued Interest [Member]
Reconciliation Of Unrecognized Tax Benefits [Line Items]
Beginning Balance	3,869	14,696	12,379
Increases in unrecognized tax benefits as a result of tax positions taken in prior years	807	453	4,429
Decreases in unrecognized tax benefits as a result of settlements with taxing authorities	(274)	(11,280)	(487)
Decreases in unrecognized tax benefits because applicable returns are no longer subject to examination			(1,625)
Unrealized tax benefits acquired in a business combination	3,567
Ending Balance	7,969	3,869	14,696
Unrecognized Income Tax Benefits [Member]
Reconciliation Of Unrecognized Tax Benefits [Line Items]
Beginning Balance	14,581	29,307	28,927
Increases in unrecognized tax benefits as a result of tax positions taken during the period	8,108	769	2,267
Increases in unrecognized tax benefits as a result of tax positions taken in prior years	807	453	4,429
Decreases in unrecognized tax benefits as a result of settlements with taxing authorities	(1,789)	(15,948)	(2,341)
Decreases in unrecognized tax benefits because applicable returns are no longer subject to examination			(3,975)
Unrealized tax benefits acquired in a business combination	10,799
Ending Balance	32,506	$ 14,581	$ 29,307
Less: Federal, state and local income tax benefits	(11,377)
Net unrecognized tax benefits that, if recognized, would impact the effective income tax rate	$ 21,129