Reconciliation of Unrecognized Tax Benefits (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Balance at beginning of period	$ 31,664	$ 26,412	$ 59,113
Increases based on tax positions taken in the current year	10,830	8,197	3,511
Increases based on tax positions taken in prior years	158	2,590	920
Decreases based on tax positions taken in prior years	(1,465)	(473)	(875)
Unrecognized tax benefits transferred to discontinued operations			(35,920)
Decreases due to settlements with tax authorities		(2,697)	(95)
Decreases due to lapse of applicable statute of limitation	(671)	(2,365)	(242)
Balance at end of period	$ 40,516	$ 31,664	$ 26,412