Income Taxes - Reconciliation of Beginning and Ending Gross Amount of Unrecognized Tax Benefits (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Income Taxes [Line Items]
Balance at beginning of year	$ 23,199	$ 24,122
Additions based on tax positions related to the current year	1,001	240
Additions for tax positions of prior years	8,928	2,186
Reductions for tax positions of prior years - Settlement	(640)	(2,547)
Reductions for tax positions of prior years - Statute of limitations	(15,111)	(802)
Balance at end of year	$ 17,377	$ 23,199