Income Taxes (Components Of Income Taxes) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Income Taxes [Line Items]
Income before income taxes	$ 30,696	$ 15,338	$ 54,646	$ 28,591
Current income tax provision	15,279	3,879	16,526	6,020
Deferred income tax provision	(2,087)	2,441	6,361	2,579
Total income tax provision	$ 13,192	$ 6,320	$ 22,887	$ 8,599
Effective tax rate	43.00%	41.20%	41.90%	30.10%