Income Taxes - Reconciliation of Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits at January 1	$ 116,070	$ 109,347	$ 118,099
Increases for positions taken in current year	7,548	4,171	2,925
Increases for positions taken in a prior year	25,239	19,318	921
Decreases for positions taken in a prior year	(1,813)	(5,637)	(1,706)
Decreases for settlements with taxing authorities	(1,143)	(2,349)	(1,097)
Decreases for lapses in the applicable statute of limitations	(26,083)	(8,780)	(9,795)
Unrecognized tax benefits at December 31	$ 119,818	$ 116,070	$ 109,347