Reconciliation of Total Segment Operating Income to Total Consolidated Income before Income Taxes (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Segment Reporting Information [Line Items]
Operating income (loss)	$ 15,724	$ 9,708
Other income (expense), net	(19)	(1)
Consolidated income before income taxes	15,705	9,707
Total segment operating income
Segment Reporting Information [Line Items]
Operating income (loss)	23,182	16,000
Other Reconciling Items
Segment Reporting Information [Line Items]
Operating income (loss)	$ (7,458)	$ (6,292)