EQUITY ROLL FORWARD (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Increase (Decrease) in Stockholders' Equity
Equity, beginning balance	$ 702,621
Net income	21,215	$ 15,934
Dividends on common stock	(5,037)
Common stock issued	642
Common stock repurchased	(7,949)
Share-based compensation	3,326
Currency translation adjustment	6,983
Pension liability, net of tax	601
Equity, ending balance	722,556
Increase (Decrease) in Temporary Equity
Temporary equity, beginning balance	1,502
Net income	(154)
Currency translation adjustment	12
Temporary equity, ending balance	1,360
Common Stock
Increase (Decrease) in Stockholders' Equity
Equity, beginning balance	4,663
Common stock issued	3
Common stock repurchased	(20)
Share-based compensation	6
Equity, ending balance	4,652
Additional Paid in Capital
Increase (Decrease) in Stockholders' Equity
Equity, beginning balance	240,136
Common stock issued	639
Share-based compensation	3,320
Equity, ending balance	244,095
Retained Earnings
Increase (Decrease) in Stockholders' Equity
Equity, beginning balance	604,905
Net income	21,174
Dividends on common stock	(5,037)
Common stock repurchased	(7,929)
Equity, ending balance	613,113
Minimum Pension Liability
Increase (Decrease) in Stockholders' Equity
Equity, beginning balance	(49,364)
Pension liability, net of tax	601
Equity, ending balance	(48,763)
Cumulative Translation Adjustment
Increase (Decrease) in Stockholders' Equity
Equity, beginning balance	(99,683)
Currency translation adjustment	6,943
Equity, ending balance	(92,740)
Noncontrolling Interest
Increase (Decrease) in Stockholders' Equity
Equity, beginning balance	1,964
Net income	195
Currency translation adjustment	40
Equity, ending balance	2,199
Total Equity
Increase (Decrease) in Stockholders' Equity
Net income	$ 21,369