Stockholders' Equity and Earnings Per Share ("EPS") - Additional Information (Detail) (USD $)	12 Months Ended			0 Months Ended			12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Apr. 15, 2011 3.875% Convertible Notes	Jul. 15, 2011 3.875% Convertible Notes Hedge and warrant agreement	Apr. 15, 2011 3.875% Convertible Notes Hedge and warrant agreement	Dec. 31, 2012 3.875% Convertible Notes Hedge and warrant agreement
Stockholders Equity Note [Line Items]
Period of warrants ratable expiration beginning July 15, 2011					60 days
Price per share of the conversion feature for the hedge and warrant agreement associated with our convertible notes							$ 64.43
Principal value				$ 250,000,000
Debt instrument maturity date				Apr. 15, 2011
Aggregate conversion settlement payment				260,000,000
Payments for settlement of 3.875% Convertible Notes	0	0	250,000,000	250,000,000
Value of common stock shares issued				10,000,000
Common stock issued in public offering				187,760
Number of shares called				186,736
Value of stock called						$ 10,000,000