SHAREHOLDERS' EQUITY Changes in Shareholders’ Equity (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Oct. 01, 2017	Sep. 30, 2018	Oct. 01, 2017
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance (in shares)			41,098
Beginning balance			$ 554,847
Net income	$ 24,380	$ 21,221	50,867	$ 39,029
Change in accounting standard cumulative-effect adjustment			(1,525)	0
Other comprehensive income (loss), net of tax	$ (595)	1,567	$ (3,900)	4,553
Ending balance (in shares)	40,472		40,472
Ending balance	$ 585,155	$ 543,773	$ 585,155	$ 543,773
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance (in shares)	40,595	41,982	41,098	42,171
Beginning balance	$ 1	$ 1	$ 1	$ 1
Purchases and retirement of common stock (in shares)	(203)	(682)	(961)	(1,268)
Issuances under equity plans, including tax benefits (in shares)	87	34	316	397
Stock-based compensation (in shares)	(7)	5	19	39
Ending balance (in shares)	40,472	41,339	40,472	41,339
Ending balance	$ 1	$ 1	$ 1	$ 1
Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	574,934	542,020	561,650	536,611
Net income	24,380	21,221	50,867	39,029
Purchases and retirement of common stock	(5,752)	(13,841)	(24,818)	(29,371)
Issuances under equity plans, including tax benefits	249	237	(1,396)	(1,778)
Stock-based compensation	3,572	1,015	9,555	6,161
Change in accounting standard cumulative-effect adjustment			1,525
Ending balance	597,383	550,652	597,383	550,652
Accumulated Other Comprehensive Loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(11,634)	(8,447)	(6,804)	(11,433)
Change in accounting standard cumulative-effect adjustment			(1,525)
Other comprehensive income (loss), net of tax	(595)	1,567	(3,900)	4,553
Ending balance	$ (12,229)	$ (6,880)	(12,229)	(6,880)
Accumulated Net Investment Gain (Loss) Attributable to Parent
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Change in accounting standard cumulative-effect adjustment			$ (1,525)	$ 0

Amount of increase to additional paid-in capital (APIC) from recognition of equity-based compensation.

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