CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) $ in Thousands	Retained Earnings	Accumulated Other Comprehensive Income/(Loss)	Common Stock Par Value	Treasury Stock	Capital in Excess of Par Value	Non-Controlling Interest	Total
Balance at Dec. 31, 2015	$ 1,185,681	$ (262,347)	$ 667	$ (270,052)	$ 495,462	$ 295	$ 1,149,706
Increase (Decrease) in Stockholders' Equity
Net Income	43,863					3	43,866
Foreign currency translation adjustments		65,171				1	65,172
Changes in unrecognized pension gains/losses and related amortization, net of tax		833					833
Changes in treasury locks, net of tax		7					7
Stock awards and option exercises			3	10,533	24,945		35,481
Cash dividends declared on common stock	(18,770)						(18,770)
Common stock repurchased and retired	(7,860)		(1)		(780)		(8,641)
Balance at Mar. 31, 2016	1,202,914	(196,336)	669	(259,519)	519,627	299	1,267,654
Balance at Dec. 31, 2016	1,197,234	(319,709)	660	(250,917)	546,682	292	1,174,242
Increase (Decrease) in Stockholders' Equity
Net Income	51,820					(15)	51,805
Foreign currency translation adjustments		23,184				2	23,186
Changes in unrecognized pension gains/losses and related amortization, net of tax		879					879
Changes in treasury locks, net of tax		7					7
Stock awards and option exercises			4	7,538	18,912		26,454
Cash dividends declared on common stock	(19,937)						(19,937)
Common stock repurchased and retired	(14,080)		(2)		(1,937)		(16,019)
Balance at Mar. 31, 2017	$ 1,215,037	$ (295,639)	$ 662	$ (243,379)	$ 563,657	$ 279	$ 1,240,617