Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Additional Paid-in Capital	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive Loss	Treasury Stock
Balance, beginning of period (in shares) at Dec. 31, 2017			181,286,547
Balance, beginning of period at Dec. 31, 2017	$ 1,844,277	$ 6,024	$ 1,813	$ 1,422,808	$ 1,607,570	$ 6,024	$ (500,049)	$ (687,865)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	531,451				531,451
Other comprehensive income (loss), net of tax	(21,287)						(21,287)
Dividends ($1.48 per share)	(245,810)				(245,810)
Repurchase of common stock	$ (390,606)							(390,606)
Share-based compensation (in shares)	0		644,678
Share-based compensation	$ 49,900		$ 6	36,812				13,082
Reclassification of certain tax effects		0			108,348		(108,348)
Balance, end of period (in shares) at Dec. 31, 2018			181,931,225
Balance, end of period at Dec. 31, 2018	1,773,949		$ 1,819	1,459,620	2,007,583		(629,684)	(1,065,389)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	423,635				423,635
Other comprehensive income (loss), net of tax	92,735						92,735
Dividends ($1.48 per share)	(237,221)				(237,221)
Repurchase of common stock	$ (296,520)							(296,520)
Share-based compensation (in shares)	0		885,311
Share-based compensation	$ 47,421		$ 9	31,384				16,028
Balance, end of period (in shares) at Dec. 31, 2019			182,816,536
Balance, end of period at Dec. 31, 2019	1,803,999	$ (78,229)	$ 1,828	1,491,004	2,193,997	$ (78,229)	(536,949)	(1,345,881)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,298				1,298
Other comprehensive income (loss), net of tax	53,532						53,532
Dividends ($1.48 per share)	(68,087)				(68,087)
Repurchase of common stock	$ (8,006)							(8,006)
Share-based compensation (in shares)	0		686,990
Share-based compensation	$ 18,278		$ 7	16,702				1,569
Retirement of treasury stock (in shares)	(15,000,000.0)		(15,000,000)
Retirement of treasury stock	$ 0		$ (150)		(764,156)			764,306
Balance, end of period (in shares) at Dec. 31, 2020			168,503,526
Balance, end of period at Dec. 31, 2020	$ 1,722,785		$ 1,685	$ 1,507,706	$ 1,284,823		$ (483,417)	$ (588,012)