Income Taxes - Reconciliation of Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits at January 1	$ 118,099	$ 100,357	$ 111,370
Increases for positions taken in current year	2,925	5,724	9,886
Increases for positions taken in a prior year	921	22,584	53,221
Decreases for positions taken in a prior year	(1,706)	(4,242)	(51,421)
Decreases for settlements with taxing authorities	(1,097)	(3,577)	(9,493)
Decreases for lapses in the applicable statute of limitations	(9,795)	(2,747)	(13,206)
Unrecognized tax benefits at December 31	$ 109,347	$ 118,099	$ 100,357