Stock-Based Compensation - Shares Issued in Connection with Stock Compensation Awards (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, Share-based Payments [Abstract]
New shares issued from available authorized shares	0	57,650	153,275	190,321
Issued from available treasury stock	587,650	0	1,096,599	7,640
Total	587,650	57,650	1,249,874	197,961
Proceeds from stock option exercises	$ 30,837	$ 2,881	$ 65,026	$ 10,092