EQUITY ROLL FORWARD (Details) $ in Thousands, TRY in Millions	3 Months Ended				9 Months Ended
	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2017 TRY	Oct. 01, 2016 USD ($)	Sep. 30, 2017 USD ($)	Oct. 01, 2016 USD ($)
Increase (Decrease) in Stockholders' Equity
Equity, beginning balance					$ 615,088
Net income	$ 24,548			$ 23,747	70,726	$ 61,514
Adjustment to Impo redemption value					27
Dividends on common stock					(14,741)
Common stock issued					3,770
Common stock repurchased					(3,263)
Share-based compensation					6,043
Noncontrolling dividend					(504)
Currency translation adjustment					21,691
Pension liability, net of tax					1,534
Equity, ending balance	700,263				700,263
Increase (Decrease) in Temporary Equity
Temporary equity, beginning balance					7,652
Net income					108
Adjustment to Impo redemption value		$ (200)	TRY (0.6)		(27)
Purchase of redeemable noncontrolling shares					(5,047)
Currency translation adjustment					(815)
Temporary equity, ending balance	1,871				1,871
Common Stock
Increase (Decrease) in Stockholders' Equity
Equity, beginning balance					4,638
Common stock issued					21
Common stock repurchased					(8)
Share-based compensation					8
Equity, ending balance	4,659				4,659
Additional Paid in Capital
Increase (Decrease) in Stockholders' Equity
Equity, beginning balance					228,564
Common stock issued					3,749
Share-based compensation					6,035
Equity, ending balance	238,348				238,348
Retained Earnings
Increase (Decrease) in Stockholders' Equity
Equity, beginning balance					550,095
Net income					70,109
Adjustment to Impo redemption value					27
Dividends on common stock					(14,741)
Common stock repurchased					(3,255)
Equity, ending balance	602,235				602,235
Minimum Pension Liability
Increase (Decrease) in Stockholders' Equity
Equity, beginning balance					(51,568)
Pension liability, net of tax					1,534
Equity, ending balance	(50,034)				(50,034)
Cumulative Translation Adjustment
Increase (Decrease) in Stockholders' Equity
Equity, beginning balance					(118,284)
Currency translation adjustment					21,550
Equity, ending balance	(96,734)				(96,734)
Noncontrolling Interest
Increase (Decrease) in Stockholders' Equity
Equity, beginning balance					1,643
Net income					509
Noncontrolling dividend					(504)
Currency translation adjustment					141
Equity, ending balance	$ 1,789				1,789
Total Equity
Increase (Decrease) in Stockholders' Equity
Net income					$ 70,618