Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adoption of accounting pronouncement	$ 1,105,265		$ 124	$ 1,064,601	$ 3,507	$ 37,033
Balance at beginning of period, (in shares) at Dec. 31, 2017			124,261
Balance at beginning of period at Dec. 31, 2017	1,105,265		$ 124	1,064,601	3,507	37,033
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	434,288					434,288
Adoption of accounting pronouncement	1,063,198		$ 119	1,079,188	(16,109)	0
Other comprehensive income (loss)	(19,616)				(19,616)
Dividends declared	(136,824)			(30,365)		(106,459)
Net issuances of restricted stock (in shares)			666
Net issuances of restricted stock	0		$ 1	(1)
Stock-based compensation	44,953			44,953
Repurchases of common stock, (in shares)			(5,849)
Repurchases of common stock	(364,868)		$ (6)			(364,862)
Balance at end of period, (in shares) at Dec. 31, 2018			119,078
Balance at end of period at Dec. 31, 2018	$ 1,063,198		$ 119	1,079,188	(16,109)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per share (usd per share)	$ 1.12
Adoption of accounting pronouncement	$ 1,063,198		119	1,079,188	(16,109)	0
Net income	454,433					454,433
Adoption of accounting pronouncement	1,063,198		$ 115	1,127,487	(19,986)	36,067	$ (558)
Other comprehensive income (loss)	(3,877)				(3,877)
Dividends declared	(145,726)					(145,726)
Net issuances of restricted stock (in shares)			647
Net issuances of restricted stock	0		$ 1	(1)
Stock-based compensation	48,300			48,300
Repurchases of common stock, (in shares)			(4,605)
Repurchases of common stock	(272,645)		$ (5)			(272,640)
Balance at end of period, (in shares) at Dec. 31, 2019			115,120
Balance at end of period at Dec. 31, 2019	$ 1,143,683		$ 115	1,127,487	(19,986)	36,067	(558)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per share (usd per share)	$ 1.24
Adoption of accounting pronouncement	$ 1,143,683		115	1,127,487	(19,986)	36,067	(558)
Net income	306,276					306,276
Adoption of accounting pronouncement	1,143,683	$ (558)	$ 113	1,179,972	(4,732)	29,936	$ (558)
Other comprehensive income (loss)	15,254				15,254
Dividends declared	(156,045)					(156,045)
Net issuances of restricted stock (in shares)			879
Net issuances of restricted stock	0		$ 1	(1)
Stock-based compensation	52,486			52,486
Repurchases of common stock, (in shares)			(2,871)
Repurchases of common stock	(155,807)		$ (3)			(155,804)
Balance at end of period, (in shares) at Dec. 31, 2020			113,128
Balance at end of period at Dec. 31, 2020	$ 1,205,289	(558)	$ 113	1,179,972	(4,732)	29,936
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per share (usd per share)	$ 1.36
Adoption of accounting pronouncement	$ 1,205,289	$ (558)	$ 113	$ 1,179,972	$ (4,732)	$ 29,936