Share-Based Compensation Expenses (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]
Option plan	$ 6,595	$ 6,375	$ 13,180	$ 11,953
Other share-based awards	9,721	6,688	16,478	11,099
Total share-based compensation before tax	16,316	13,063	29,658	23,052
Tax benefit	6,085	4,885	11,062	8,614
Total share-based compensation expense included in net income	$ 10,231	$ 8,178	$ 18,596	$ 14,438