CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Shares	Noncontrolling Interests
Beginning Balance at Dec. 31, 2016	$ 712,206	$ 9,858	$ 309,417	$ 2,236,071	$ (329,037)	$ (1,514,832)	$ 729
Beginning Balance (in shares) at Dec. 31, 2016		65,674,000
Increase (Decrease) in Stockholders' Equity
Net income	247,475			247,503			(28)
Unrecognized amounts from defined benefit pension plans, net of tax	10,662				10,662
Unrealized gain on derivatives designated and qualifying as cash flow hedges, net of tax	288				288
Currency translation adjustment	71,016				70,901		115
Cash dividends declared - $1.90, $1.64, and $1.44 per share during the year 2019, 2018 and 2017, respectively	(95,355)			(95,355)
Stock-based compensation activity	29,325		24,892			4,433
Issuance of shares under benefit plans (in shares)		470,000
Purchase of shares for treasury	(43,164)					(43,164)
Purchase of shares for treasury (in shares)		(481,000)
Ending Balance at Dec. 31, 2017	932,453	$ 9,858	334,309	2,388,219	(247,186)	(1,553,563)	816
Ending Balance (in shares) at Dec. 31, 2017		65,663,000
Increase (Decrease) in Stockholders' Equity
Net income	286,993			287,066			(73)
Unrecognized amounts from defined benefit pension plans, net of tax	3,228				3,228
Unrealized gain on derivatives designated and qualifying as cash flow hedges, net of tax	819				819
Currency translation adjustment	(50,693)				(50,600)		(93)
Cash dividends declared - $1.90, $1.64, and $1.44 per share during the year 2019, 2018 and 2017, respectively	(106,802)			(106,802)
Stock-based compensation activity	23,244		21,956			1,288
Issuance of shares under benefit plans (in shares)		158,000
Purchase of shares for treasury	(201,650)					(201,650)
Purchase of shares for treasury (in shares)		(2,275,000)
Stockholders' Equity, Other			4,043	(4,043)
Equity (Increase) Decrease from Transactions with Noncontrolling Interest Holders	0
Ending Balance at Dec. 31, 2018	$ 887,592	$ 9,858	360,308	2,564,440	(293,739)	(1,753,925)	650
Ending Balance (in shares) at Dec. 31, 2018	63,545,878	63,546,000
Increase (Decrease) in Stockholders' Equity
Net income	$ 293,083			293,109			(26)
Unrecognized amounts from defined benefit pension plans, net of tax	11,503				11,503
Unrealized gain on derivatives designated and qualifying as cash flow hedges, net of tax	(68)				(68)
Currency translation adjustment	6,735				6,454		281
Cash dividends declared - $1.90, $1.64, and $1.44 per share during the year 2019, 2018 and 2017, respectively	(117,950)			(117,950)
Stock-based compensation activity	30,971		26,116			4,855
Issuance of shares under benefit plans (in shares)		467,000
Purchase of shares for treasury	$ (292,693)					(292,693)
Purchase of shares for treasury (in shares)	(3,400,000)	(3,421,000)
Stockholders' Equity, Other	$ (96)		3,022	(3,118)
Ending Balance at Dec. 31, 2019	$ 819,077	$ 9,858	$ 389,446	$ 2,736,481	$ (275,850)	$ (2,041,763)	$ 905
Ending Balance (in shares) at Dec. 31, 2019	60,592,096	60,592,000