Earnings Per Share - Summary of Earnings Per Share, Basic and Diluted (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share [Abstract]
Net income	$ 209,851	$ 188,817	$ 158,488	$ 147,060	$ 235,510	$ 225,805	$ 261,651	$ 172,107	$ 704,216	$ 895,073	$ 811,483	[1],[2]
Denominator for basic earnings per share (in shares)	83,514	83,719	83,895	84,902	86,600	86,662	86,360	85,941	84,005	86,401	88,750	[2]
Dilutive securities (in shares)									2,714	3,669	3,401
Denominator for diluted earnings per share (in shares)	85,846	86,273	86,570	88,205	90,427	90,522	90,131	89,244	86,719	90,070	92,151	[2]
Basic earnings per share (in usd per share)	$ 2.51	$ 2.26	$ 1.89	$ 1.73	$ 2.72	$ 2.61	$ 3.03	$ 2.00	$ 8.38	$ 10.36	$ 9.14	[2]
Diluted earnings per share (in usd per share)	$ 2.44	$ 2.19	$ 1.83	$ 1.67	$ 2.60	$ 2.49	$ 2.90	$ 1.93	$ 8.12	$ 9.94	$ 8.81	[2]

[1] The Company applied the modified retrospective transition method when adopting ASU 2016-02 "Leases", therefore the Company's 2018 prior results were not restated to reflect ASU 2016-02. Refer to footnote 14.

[2] The Company applied the modified retrospective transition method when adopting ASU 2016-02 "Leases", therefore the Company's 2018 prior results were not restated to reflect ASU 2016-02. Refer to footnote 14.