Share-Based Compensation Expenses (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Option plan	$ 6,210	$ 6,698	$ 17,772	$ 19,878
Other share-based awards	(3,139)	5,689	15,680	22,167
Total share-based compensation before tax	3,071	12,387	33,452	42,045
Tax benefit	1,146	4,621	12,478	15,683
Total share-based compensation expense included in net income	$ 1,925	$ 7,766	$ 20,974	$ 26,362