Equity Compensation - Stock Options Granted and Exercised (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Shares subject to stock options granted	0	0	154,000	156,500
Weighted average grant date fair value per share	$ 0.00	$ 0.00	$ 9.16	$ 31.36
Shares subject to stock options exercised	0	4,855	0	202,820
Intrinsic value of stock options exercised	$ 0	$ 14	$ 0	$ 4,802
Proceeds received from stock options exercised	0	254	0	8,345
Tax benefits realized from stock options exercised	$ 0	$ 5	$ 0	$ 1,602