Stockholders' Equity - Summary of Stock Appreciation Rights Activity (Parenthetical) (Detail) (Stock Appreciation Rights [Member], USD $)	Sep. 30, 2014
Stock Appreciation Rights [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Closing stock price of common stock	$ 98.87

Price of a single share of a number of saleable stocks of a company.

No definition available.