Earnings Per Share - Summary of Earnings Per Share, Basic and Diluted (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Earnings Per Share [Abstract]
Net income	$ 123,693	$ 111,090	[1]
Denominator for basic earnings per share (in shares)	92,108	92,516	[1]
Dilutive securities (in shares)	2,452	2,514
Denominator for diluted earnings per share (in shares)	94,560	95,030	[1]
Basic earnings per share (in dollars per share)	$ 1.34	$ 1.20	[1]
Diluted earnings per share (in dollars per share)	$ 1.31	$ 1.17	[1]

[1] Reflects the impact of the Company's adoption of Accounting Standards Update 2016-09, Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting, to simplify several aspects of the accounting for share-based compensation, including the income tax consequences.