Stockholders' Equity - Additional Information (Detail) (USD $)	1 Months Ended	6 Months Ended
	Aug. 01, 2007	Jun. 30, 2011
Stockholders Equity Note [Line Items]
Amount approved for repurchases under stock buyback program	$ 250,000,000
Treasury stock shares acquired		8,025
Treasury stock repurchased, value		242,000
Amount authorized to purchase the Company's outstanding common stock under the program		113,000,000
Treasury stock shares acquired from employees		130,768
Purchase price for treasury stock acquired from employees		$ 4,000,000
Dividend Declared
Stockholders Equity Note [Line Items]
Subsequent event, date		Jul. 27, 2011
Dividend declaration date		Jul. 27, 2011
Dividend per share, declared		$ 0.05
Dividend payment date		Sep. 30, 2011
Dividend record date		Sep. 15, 2011