Consolidated Statements of Equity - USD ($) $ in Thousands	Total	Common Stock $1 Par Value	Capital in Excess of Par Value	Retained Earnings	Cumulative Other Comprehensive Income (Loss)	Common Shares in Treasury	Total Parent Stockholders’ Equity	Noncontrolling Shareholders’ Interests in Consolidated Subsidiaries
Beginning Balance at Dec. 31, 2014	$ 884,261	$ 87,850	$ 5,742	$ 1,867,126	$ (530,602)	$ (586,324)	$ 843,792	$ 40,469
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	215,804			212,766			212,766	3,038
Net income attributable to noncontrolling shareholders' interests	3,038
Other comprehensive income (loss)	16,608				20,835		20,835	(4,227)
Comprehensive income (loss)	232,412			212,766	20,835		233,601	(1,189)
Dividends payable to noncontrolling shareholder	(917)							(917)
Accelerated share repurchase program	0		2,010	37,990		(40,000)
Share repurchase program	(108,821)					(108,821)	(108,821)
Stock compensation plans, including tax benefit	34,556		8,554	1,921		24,081	34,556
Cash dividends - $0.42 per share	(23,880)			(23,880)			(23,880)
Ending Balance at Dec. 31, 2015	1,017,611	87,850	16,306	2,095,923	(509,767)	(711,064)	979,248	38,363
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	251,294			248,381			248,381	2,913
Net income attributable to noncontrolling shareholders' interests	2,913
Other comprehensive income (loss)	(39,957)				(35,384)		(35,384)	(4,573)
Comprehensive income (loss)	211,337			248,381	(35,384)		212,997	(1,660)
Dividends payable to noncontrolling shareholder	(804)							(804)
Acquisition of business	18,323							18,323
Share repurchase program	(107,999)					(107,999)	(107,999)
Stock compensation plans, including tax benefit	14,596		9,570	(52)		5,078	14,596
Cash dividends - $0.42 per share	(22,828)			(22,828)			(22,828)
Ending Balance at Dec. 31, 2016	1,130,236	87,850	25,876	2,321,424	(545,151)	(813,985)	1,076,014	54,222
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	96,745			95,400			95,400
Net income attributable to noncontrolling shareholders' interests	1,345
Other comprehensive income (loss)	70,048				66,673		66,673	3,375
Comprehensive income (loss)	166,793			95,400	66,673		162,073	4,720
Dividends payable to noncontrolling shareholder	(282)							(282)
Share repurchase program	(90,868)					(90,868)	(90,868)
Stock compensation plans, including tax benefit	1,791		(5,136)	(538)		7,465	1,791
Cash dividends - $0.42 per share	(21,914)			(21,914)			(21,914)
Ending Balance at Dec. 31, 2017	$ 1,185,756	$ 87,850	$ 20,740	$ 2,394,372	$ (478,478)	$ (897,388)	$ 1,127,096	$ 58,660