Earnings Per Share - Summary of Earnings Per Share, Basic and Diluted (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share [Abstract]
Net income	$ 188,817	$ 158,488	$ 147,060	$ 225,805	$ 261,651	$ 172,107	$ 494,365	$ 659,563
Denominator for basic earnings per share (in shares)	83,719			86,662			84,170	86,332
Dilutive securities (in shares)	2,554			3,860			2,836	3,644
Denominator for diluted earnings per share (in shares)	86,273			90,522			87,006	89,976
Basic earnings per share (in dollars per share)	$ 2.26			$ 2.61			$ 5.87	$ 7.64
Diluted earnings per share (in dollars per share)	$ 2.19			$ 2.49			$ 5.68	$ 7.33