EQUITY ROLL FORWARD (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Common Stock, Dividends, Per Share, Cash Paid	$ 0.155	$ 0.145
Increase (Decrease) in Stockholders' Equity
Equity, beginning balance	$ 798,669
Net income	10,792	$ 9,127
Equity, ending balance	753,466
Temporary equity, beginning balance	(236)	518
Net income	(38)	(103)
Temporary Equity, Foreign Currency Translation Adjustments	29	(7)
Temporary equity, ending balance	(245)	408
Common Stock
Increase (Decrease) in Stockholders' Equity
Equity, beginning balance	4,639	4,632
Stock Issued During Period, Value, New Issues	2	6
Stock Repurchased and Retired During Period, Value	(35)	(9)
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	8	8
Equity, ending balance	4,614	4,637
Additional Paid in Capital
Increase (Decrease) in Stockholders' Equity
Equity, beginning balance	269,656	257,535
Stock Issued During Period, Value, New Issues	869	1,245
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	4,344	3,222
Equity, ending balance	274,869	262,002
Retained Earnings
Increase (Decrease) in Stockholders' Equity
Equity, beginning balance	712,460	654,724
Net income	10,643	9,056
Dividends, Common Stock, Cash	(7,240)	(6,723)
Stock Repurchased and Retired During Period, Value	(16,946)	(4,320)
Equity, ending balance	698,917	652,737
Minimum Pension Liability
Increase (Decrease) in Stockholders' Equity
Equity, beginning balance	(50,089)	(48,585)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	716	509
Equity, ending balance	(49,373)	(48,076)
Cumulative Translation Adjustment
Increase (Decrease) in Stockholders' Equity
Equity, beginning balance	(140,121)	(134,434)
Currency translation adjustment	(37,727)	(2,771)
Equity, ending balance	(177,848)	(137,205)
Noncontrolling Interest
Increase (Decrease) in Stockholders' Equity
Equity, beginning balance	2,124	1,955
Net income	187	174
Currency translation adjustment	(24)	(32)
Equity, ending balance	2,287	2,097
Total Equity
Increase (Decrease) in Stockholders' Equity
Equity, beginning balance	798,669	735,827
Net income	10,830	9,230
Dividends, Common Stock, Cash	(7,240)	(6,723)
Stock Issued During Period, Value, New Issues	871	1,251
Stock Repurchased and Retired During Period, Value	(16,981)	(4,329)
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	4,352	3,230
Currency translation adjustment	(37,751)	(2,803)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	716	509
Equity, ending balance	$ 753,466	$ 736,192