Stock-Based Compensation - Shares Issued in Connection with Stock Compensation Awards (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
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	65,200	157,124	67,075	171,474
Total	65,200	157,124	67,075	171,474
Proceeds from stock option exercises	$ 3,490	$ 8,222	$ 3,586	$ 8,950