Consolidated Statements Of Shareholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Cumulative Effect, Period of Adoption, Adjustment	Cumulative Effect, Period of Adoption, Adjustment Retained Earnings
Shareholders' equity (shares) at Dec. 31, 2019		270,235
Shareholders' equity at Dec. 31, 2019	$ 5,458,180	$ 2,702	$ 3,235,149	$ (245)	$ 2,220,574	$ (735)	$ (735)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock option exercises (shares)		1
Stock option exercises	51		51
Stock issuances (shares)		738
Share issuances	4,095	$ 7	4,088
Dividends declared	(32,609)				(32,609)
Share repurchases (shares)		(2,825)
Share repurchases	(95,676)	$ (28)			(95,648)
Cash paid for shares withheld for taxes	(14,838)				(14,838)
Share-based compensation	8,187		8,187
Net income	203,711				203,711
Other comprehensive income	25			25
Shareholders' equity (shares) at Mar. 31, 2020		268,149
Shareholders' equity at Mar. 31, 2020	5,530,391	$ 2,681	3,247,475	(220)	2,280,455
Shareholders' equity (shares) at Dec. 31, 2020		266,464
Shareholders' equity at Dec. 31, 2020	6,569,989	$ 2,665	3,261,412	(145)	3,306,057
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock option exercises (shares)		1
Stock option exercises	11		11
Stock issuances (shares)		505
Share issuances	4,181	$ 5	4,176
Dividends declared	(37,325)				(37,325)
Share repurchases (shares)		(3,333)
Share repurchases	(153,703)	$ (34)			(153,669)
Cash paid for shares withheld for taxes	(10,566)				(10,566)
Share-based compensation	8,555		8,555
Net income	304,107				304,107
Other comprehensive income	25			25
Shareholders' equity (shares) at Mar. 31, 2021		263,637
Shareholders' equity at Mar. 31, 2021	$ 6,685,274	$ 2,636	$ 3,274,154	$ (120)	$ 3,408,604