Summary of Common Stock and Additional Paid-in Capital Activity (Detail) (USD $) In Thousands	9 Months Ended
	Sep. 30, 2011
Stockholders Equity Note [Line Items]
Beginning Balance	$ 465,467
Income tax benefit of common stock options exercised	4,729
Common stock issued pursuant to stock-based compensation plans, net	10,291
Stock-based compensation expense	19,435
Repurchase of common stock	(124,384)
Ending Balance	$ 375,538