Share-Based Compensation Expenses (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Option plan	$ 6,698	$ 6,310	$ 19,878	$ 18,263
Other share-based awards	5,689	8,103	22,167	19,202
Total share-based compensation before tax	12,387	14,413	42,045	37,465
Tax benefit	4,621	5,376	15,683	13,990
Total share-based compensation expense included in net income	$ 7,766	$ 9,037	$ 26,362	$ 23,475