Share-Based Compensation - Stock Compensation Expense and Total Related Tax Benefit Recognized (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock compensation expense	$ 11,663	$ 11,877	$ 21,570	$ 22,171
Recognized tax benefit	$ 1,491	$ 1,183	$ 2,734	$ 2,126