Consolidated Statement of Equity - USD ($) $ in Thousands	Total	Common Stock	Treasury Stock	Capital in Excess of Par Value	Retained Earnings [Member]	Accumulated Other Comprehensive Income	Noncontrolling Interest
Balance at beginning of period at Dec. 31, 2020	$ 1,752,621	$ 174,792	$ (4,075)	$ 981,934	$ 560,731	$ 39,366	$ (127)
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Comprehensive income	233,960	0	0	0	228,879	5,005	76
Dividends, Common Stock	(35,568)	0	0	0	35,568	0	0
Stock option exercises	2,364	99	0	2,265	0	0	0
Restricted stock awards, net of forfeitures	0	163	0	(163)	0	0	0
Employee share-based compensation earned	3,500	0	0	3,500	0	0	0
Purchase of Company common stock	(106,217)	0	(2,142)	(12,304)	(91,771)	0	0
Other	0	0	0	0	0	0	0
Balance at end of period at Mar. 31, 2021	1,850,660	175,054	(6,217)	975,232	662,271	44,371	(51)
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Stockholders' Equity, Period Increase (Decrease) | Accounting Standards Update 2016-13 [Member]	0	0	0	0	0	0	0
Balance at beginning of period at Dec. 31, 2021	1,909,449	166,822	(3,708)	979,096	727,021	40,214	4
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Comprehensive income	226,846	0	0	0	219,513	7,279	54
Dividends, Common Stock	$ (39,964)	0	0	0	(39,964)	0	0
Dividends declared per share
Stock option exercises	$ 272	7	0	265	0	0	0
Restricted stock awards, net of forfeitures	0	147	0	(147)	0	0	0
Employee share-based compensation earned	3,687	0	0	3,687	0	0	0
Purchase of Company common stock	(256,355)	0	(4,104)	(24,613)	(227,638)	0	0
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders	162	0	0	0	0	0	162
Other	(1,127)	0	0	(1,127)	0	0	0
Balance at end of period at Mar. 31, 2022	$ 1,842,646	$ 166,976	$ (7,812)	$ 957,161	$ 678,932	$ 47,493	$ (104)