Consolidated Statement of Equity - USD ($) $ in Thousands	Total	Total Parent Stockholders’ Equity	Common Stock $1 Par Value	Capital in Excess of Par Value	Retained Earnings	Cumulative Other Comprehensive (Loss) Income	Common Shares in Treasury	Noncontrolling Shareholders’ Interests in Consolidated Subsidiaries
Beginning Balance at Dec. 31, 2017	$ 1,185,756	$ 1,127,096	$ 87,850	$ 20,740	$ 2,394,372	$ (478,478)	$ (897,388)	$ 58,660
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	80,563	76,586			76,586			3,977
Other comprehensive income (loss)	14,652	16,889				16,889		(2,237)
Share repurchase program	(30,183)	(30,183)					(30,183)
Stock compensation plans	2,793	2,793		384	(106)		2,515
Cash dividends	(21,138)	(21,138)			(21,138)
Ending Balance at Dec. 31, 2018	1,232,443	1,172,043	87,850	21,124	2,449,714	(461,589)	(925,056)	60,400
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	98,317	96,404			96,404			1,913
Other comprehensive income (loss)	14,804	14,009				14,009		795
Stock compensation plans	3,237	3,237		1,051	(87)		2,273
Cash dividends	(21,068)	(21,068)			(21,068)
Ending Balance at Dec. 31, 2019	1,327,733	1,264,625	87,850	22,175	2,524,963	(447,580)	(922,783)	63,108
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	143,904	142,789			142,789			1,115
Other comprehensive income (loss)	2,950
Other comprehensive loss, excluding currency loss charged to equity as part of acquisition of noncontrolling shareholder interest	14,698	12,419				12,419		2,279
Acquisition of noncontrolling shareholders' interest	(62,272)	(17,462)		(5,714)		(11,748)		(44,810)
Stock compensation plans	7,660	7,660		4,354	(53)		3,359
Cash dividends	(21,132)	(21,132)			(21,132)
Ending Balance at Dec. 31, 2020	$ 1,410,591	$ 1,388,899	$ 87,850	$ 20,815	$ 2,646,567	$ (446,909)	$ (919,424)	$ 21,692