Reconciliation of Beginning and Ending Amount of Consolidated Liability for Unrecognized Income Tax Benefits (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Tax Contingency [Line Items]
Beginning balance	$ 18,857	$ 23,196	$ 25,978
Additions for tax positions related to current year	1,258	1,294	1,225
Settlements due to lapse of time	(3,504)	(5,633)	(4,007)
Ending balance	$ 16,611	$ 18,857	$ 23,196