Stock-Based Compensation - Shares Issued in Connection with Stock Compensation Awards (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
New shares issued from available authorized shares	0	0	0	0
Issued from available treasury stock	157,124	54,950	171,474	384,775
Total	157,124	54,950	171,474	384,775
Proceeds from stock option exercises	$ 8,222	$ 2,830	$ 8,950	$ 20,109