Earnings Per Share - Summary of Earnings Per Share, Basic and Diluted (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020
Earnings Per Share [Abstract]
Net income	$ 196,247	$ 184,239	$ 158,488	$ 147,060	$ 380,486	$ 305,548
Denominator for basic earnings per share (in shares)	83,141		83,895		83,307	84,399
Dilutive securities (in shares)	2,154		2,675		2,221	2,981
Denominator for diluted earnings per share (in shares)	85,295		86,570		85,528	87,380
Basic earnings per share (in dollars per share)	$ 2.36		$ 1.89		$ 4.57	$ 3.62
Diluted earnings per share (in dollars per share)	$ 2.30		$ 1.83		$ 4.45	$ 3.50