Stock-Based Compensation and Other Employee Benefit Plans (Summary of Tax Benefits from Stock-Based Compensation) (Detail) (USD $)	3 Months Ended				9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Share-based Compensation [Abstract]
Stock-based compensation expense	$ 3,000,000		$ 1,200,000		$ 9,647,000		$ 3,351,000
Income tax benefit from stock-based compensation	4,500,000		700,000		7,700,000		1,600,000
Excess tax benefit from stock-based compensation	$ 3,000,000	[1]	$ 200,000	[1]	$ 4,446,000	[1]	$ 302,000	[1]

[1] Excess tax benefits, which represent cash flows from tax deductions in excess of the tax effect of compensation expense recognized for stock options exercised and vested restricted shares, are classified as financing cash flows in the Company’s condensed unaudited consolidated statements of cash flows.