CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common stock	Paid-in capital	Paid-in capital Cumulative Effect, Period of Adoption, Adjustment	Paid-in capital Cumulative Effect, Period of Adoption, Adjusted Balance	Treasury stock	Accumulated other comprehensive income (loss)	Retained earnings	Retained earnings Cumulative Effect, Period of Adoption, Adjustment	Retained earnings Cumulative Effect, Period of Adoption, Adjusted Balance
Balance, beginning of period at Dec. 31, 2019		$ 371,353	$ 1,869,719			$ (283,196)	$ 72,708	$ 2,278,650
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Reissuance of treasury stock, net under share-based compensation plans			(18,667)			9,768
Equity compensation			8,143
Repurchase of common stock						(119,997)
Other comprehensive income (loss), net of tax	$ 72,704						72,704
Net income	163,852							163,852
Cash dividends								(41,682)
Balance, end of period at Jun. 30, 2020	4,383,355	371,353	1,859,195			(393,425)	145,412	2,400,820
Balance, beginning of period at Dec. 31, 2019		371,353	1,869,719			(283,196)	72,708	2,278,650
Balance, end of period at Dec. 31, 2020	$ 4,698,986	371,353	1,862,042	$ (68,289)	$ 1,793,753	(393,326)	216,821	2,642,096	$ 68,289	$ 2,710,385
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accounting Standards Update [Extensible Enumeration]	us-gaap:AccountingStandardsUpdate202006Member
Balance, beginning of period at Mar. 31, 2020		371,353	1,855,371			(393,425)	1,224	2,407,305
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Reissuance of treasury stock, net under share-based compensation plans			0			0
Equity compensation			3,824
Repurchase of common stock						0
Other comprehensive income (loss), net of tax	$ 144,188						144,188
Net income	14,047							14,047
Cash dividends								(20,532)
Balance, end of period at Jun. 30, 2020	4,383,355	371,353	1,859,195			(393,425)	145,412	2,400,820
Balance, beginning of period at Dec. 31, 2020	4,698,986	371,353	1,862,042	$ (68,289)	$ 1,793,753	(393,326)	216,821	2,642,096	$ 68,289	$ 2,710,385
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Reissuance of treasury stock, net under share-based compensation plans			(15,745)			8,776
Equity compensation			8,252
Repurchase of common stock						0
Other comprehensive income (loss), net of tax	(47,539)						(47,539)
Net income	303,072							303,072
Cash dividends	(41,100)							(41,095)
Balance, end of period at Jun. 30, 2021	4,914,707	371,353	1,786,260			(384,550)	169,282	2,972,362
Balance, beginning of period at Mar. 31, 2021		371,353	1,782,041			(384,550)	123,565	2,839,884
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Reissuance of treasury stock, net under share-based compensation plans			(348)			0
Equity compensation			4,567
Repurchase of common stock						0
Other comprehensive income (loss), net of tax	45,717						45,717
Net income	153,051							153,051
Cash dividends								(20,573)
Balance, end of period at Jun. 30, 2021	$ 4,914,707	$ 371,353	$ 1,786,260			$ (384,550)	$ 169,282	$ 2,972,362