GUARANTOR/NON-GUARANTOR FINANCIAL INFORMATION - Condensed Consolidated Statements of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 28, 2019	Sep. 29, 2018	Sep. 28, 2019	Sep. 29, 2018
Cash flows from operating activities:
Net earnings	$ 42,263	$ 6,991	$ 122,064	$ 82,151
Adjustments to reconcile net earnings to net cash flows from operations:
Depreciation and amortization			60,424	62,018
Noncash loss on trading securities			(48)	(62)
Impairment of property, plant and equipment			0	4,197
Impairment of goodwill & intangible assets			0	15,780
Loss on divestiture of grinding media business	0	0	0	6,084
Stock-based compensation			8,889	8,076
Defined benefit pension plan benefit			(382)	(1,713)
Contribution to defined benefit pension plan			(17,426)	(1,555)
Gain on sale of property, plant and equipment			(465)	(353)
Equity in earnings in nonconsolidated subsidiaries	0	0	0	0
Deferred income taxes	1,388	(1,686)	7,098	814
Changes in assets and liabilities:
Net working capital			72,575	(96,912)
Other noncurrent liabilities			(4,563)	(1,249)
Income taxes refundable			(8,936)	(9,223)
Net cash flows from operating activities			239,230	68,053
Cash flows from investing activities:
Purchase of property, plant and equipment			(71,981)	(48,919)
Proceeds from sale of assets			1,325	64,786
Acquisitions, net of cash acquired			(81,841)	(125,309)
Settlement of net investment hedge			11,184	(1,621)
Other, net			2,117	(2,371)
Net cash flows from investing activities			(139,196)	(113,434)
Cash flows from financing activities:
Proceeds from short-term agreements			9,284	3,217
Proceeds from long-term borrowings			31,000	236,936
Principal payments on long-term borrowings			(10,578)	(252,952)
Settlement of financial derivatives			0	(2,467)
Debt issuance costs			0	(2,322)
Principal payments on long-term intercompany note			0
Dividends paid			(24,554)	(25,415)
Dividends to noncontrolling interest			(6,549)	(5,737)
Intercompany dividends			0	0
Purchase of noncontrolling interest			(27,845)	(5,510)
Intercompany capital contribution			0	0
Purchase of treasury shares			(55,172)	(86,919)
Proceeds from exercises under stock plans			3,211	6,376
Purchase of common treasury shares - stock plan exercises			(1,456)	(1,914)
Net cash flows from financing activities			(82,659)	(136,707)
Effect of exchange rate changes on cash and cash equivalents			(3,385)	(15,095)
Net change in cash and cash equivalents			13,990	(197,183)
Cash, cash equivalents, and restricted cash—beginning of year			313,210	492,805
Cash, cash equivalents, and restricted cash—end of period	327,200	295,622	327,200	295,622
Eliminations
Cash flows from operating activities:
Net earnings	(41,396)	(13,592)	(93,156)	(92,212)
Adjustments to reconcile net earnings to net cash flows from operations:
Depreciation and amortization			0	0
Noncash loss on trading securities			0	0
Impairment of property, plant and equipment				0
Impairment of goodwill & intangible assets				0
Loss on divestiture of grinding media business				0
Stock-based compensation			0	0
Defined benefit pension plan benefit			0	0
Contribution to defined benefit pension plan			0	0
Gain on sale of property, plant and equipment			0	0
Equity in earnings in nonconsolidated subsidiaries	41,114	13,650	92,692	93,426
Deferred income taxes			0	0
Changes in assets and liabilities:
Net working capital			541	(1,277)
Other noncurrent liabilities			0	0
Income taxes refundable			0	0
Net cash flows from operating activities			77	(63)
Cash flows from investing activities:
Purchase of property, plant and equipment			0	0
Proceeds from sale of assets			0	0
Acquisitions, net of cash acquired			0	0
Settlement of net investment hedge			0	0
Other, net			(77)	63
Net cash flows from investing activities			(77)	63
Cash flows from financing activities:
Proceeds from short-term agreements			0	0
Proceeds from long-term borrowings			0	0
Principal payments on long-term borrowings			0	0
Settlement of financial derivatives				0
Debt issuance costs				0
Principal payments on long-term intercompany note			0
Dividends paid			0	0
Dividends to noncontrolling interest			0	0
Intercompany dividends			0	0
Purchase of noncontrolling interest			0	0
Intercompany capital contribution			0	0
Purchase of treasury shares			0	0
Proceeds from exercises under stock plans			0	0
Purchase of common treasury shares - stock plan exercises			0	0
Net cash flows from financing activities			0	0
Effect of exchange rate changes on cash and cash equivalents			0	0
Net change in cash and cash equivalents			0	0
Cash, cash equivalents, and restricted cash—beginning of year			0	0
Cash, cash equivalents, and restricted cash—end of period	0	0	0	0
Parent
Cash flows from operating activities:
Net earnings	40,144	4,448	118,022	76,689
Adjustments to reconcile net earnings to net cash flows from operations:
Depreciation and amortization			19,891	19,498
Noncash loss on trading securities			0	0
Impairment of property, plant and equipment				0
Impairment of goodwill & intangible assets				0
Loss on divestiture of grinding media business				2,518
Stock-based compensation			8,889	8,076
Defined benefit pension plan benefit			0	0
Contribution to defined benefit pension plan			0	0
Gain on sale of property, plant and equipment			103	7
Equity in earnings in nonconsolidated subsidiaries	(39,097)	(9,609)	(83,849)	(55,487)
Deferred income taxes			3,869	729
Changes in assets and liabilities:
Net working capital			94,054	(28,948)
Other noncurrent liabilities			1,005	(762)
Income taxes refundable			(4,488)	(23,256)
Net cash flows from operating activities			157,496	(936)
Cash flows from investing activities:
Purchase of property, plant and equipment			(33,321)	(16,940)
Proceeds from sale of assets			35	39
Acquisitions, net of cash acquired			0	(57,805)
Settlement of net investment hedge			11,184	(1,621)
Other, net			(30,475)	28,299
Net cash flows from investing activities			(52,577)	(48,028)
Cash flows from financing activities:
Proceeds from short-term agreements			0	0
Proceeds from long-term borrowings			31,000	236,936
Principal payments on long-term borrowings			(10,000)	(252,219)
Settlement of financial derivatives				(2,467)
Debt issuance costs				(2,322)
Principal payments on long-term intercompany note			0
Dividends paid			(24,554)	(25,415)
Dividends to noncontrolling interest			0	0
Intercompany dividends			63,650	123,363
Purchase of noncontrolling interest			(22,805)	0
Intercompany capital contribution			(13,284)	(3,492)
Purchase of treasury shares			(55,172)	(86,919)
Proceeds from exercises under stock plans			3,211	6,376
Purchase of common treasury shares - stock plan exercises			(1,456)	(1,914)
Net cash flows from financing activities			(29,410)	(8,073)
Effect of exchange rate changes on cash and cash equivalents			0	0
Net change in cash and cash equivalents			75,509	(57,037)
Cash, cash equivalents, and restricted cash—beginning of year			104,256	83,329
Cash, cash equivalents, and restricted cash—end of period	179,765	26,292	179,765	26,292
Guarantors
Cash flows from operating activities:
Net earnings	27,154	14,792	61,174	70,748
Adjustments to reconcile net earnings to net cash flows from operations:
Depreciation and amortization			10,201	10,564
Noncash loss on trading securities			0	0
Impairment of property, plant and equipment				0
Impairment of goodwill & intangible assets				0
Loss on divestiture of grinding media business				0
Stock-based compensation			0	0
Defined benefit pension plan benefit			0	0
Contribution to defined benefit pension plan			0	0
Gain on sale of property, plant and equipment			81	(27)
Equity in earnings in nonconsolidated subsidiaries	(2,017)	(4,041)	(8,843)	(37,939)
Deferred income taxes			0	1,791
Changes in assets and liabilities:
Net working capital			(15,715)	(40,255)
Other noncurrent liabilities			(5,461)	387
Income taxes refundable			(2,229)	(1,066)
Net cash flows from operating activities			39,208	4,203
Cash flows from investing activities:
Purchase of property, plant and equipment			(12,462)	(9,546)
Proceeds from sale of assets			26	232
Acquisitions, net of cash acquired			(63,141)	0
Settlement of net investment hedge			0	0
Other, net			27,878	(3,683)
Net cash flows from investing activities			(47,699)	(12,997)
Cash flows from financing activities:
Proceeds from short-term agreements			0	0
Proceeds from long-term borrowings			0	0
Principal payments on long-term borrowings			0	0
Settlement of financial derivatives				0
Debt issuance costs				0
Principal payments on long-term intercompany note			(42,574)
Dividends paid			0	0
Dividends to noncontrolling interest			0	0
Intercompany dividends			47,541	11,296
Purchase of noncontrolling interest			0	0
Intercompany capital contribution			0	3,492
Purchase of treasury shares			0	0
Proceeds from exercises under stock plans			0	0
Purchase of common treasury shares - stock plan exercises			0	0
Net cash flows from financing activities			4,967	14,788
Effect of exchange rate changes on cash and cash equivalents			(31)	(670)
Net change in cash and cash equivalents			(3,555)	5,324
Cash, cash equivalents, and restricted cash—beginning of year			5,518	5,304
Cash, cash equivalents, and restricted cash—end of period	1,963	10,628	1,963	10,628
Non- Guarantors
Cash flows from operating activities:
Net earnings	16,361	1,343	36,024	26,926
Adjustments to reconcile net earnings to net cash flows from operations:
Depreciation and amortization			30,332	31,956
Noncash loss on trading securities			(48)	(62)
Impairment of property, plant and equipment				4,197
Impairment of goodwill & intangible assets				15,780
Loss on divestiture of grinding media business				3,566
Stock-based compensation			0	0
Defined benefit pension plan benefit			(382)	(1,713)
Contribution to defined benefit pension plan			(17,426)	(1,555)
Gain on sale of property, plant and equipment			(649)	(333)
Equity in earnings in nonconsolidated subsidiaries	0	0	0	0
Deferred income taxes			3,229	(1,706)
Changes in assets and liabilities:
Net working capital			(6,305)	(26,432)
Other noncurrent liabilities			(107)	(874)
Income taxes refundable			(2,219)	15,099
Net cash flows from operating activities			42,449	64,849
Cash flows from investing activities:
Purchase of property, plant and equipment			(26,198)	(22,433)
Proceeds from sale of assets			1,264	64,515
Acquisitions, net of cash acquired			(18,700)	(67,504)
Settlement of net investment hedge			0	0
Other, net			4,791	(27,050)
Net cash flows from investing activities			(38,843)	(52,472)
Cash flows from financing activities:
Proceeds from short-term agreements			9,284	3,217
Proceeds from long-term borrowings			0	0
Principal payments on long-term borrowings			(578)	(733)
Settlement of financial derivatives				0
Debt issuance costs				0
Principal payments on long-term intercompany note			42,574
Dividends paid			0	0
Dividends to noncontrolling interest			(6,549)	(5,737)
Intercompany dividends			(111,191)	(134,659)
Purchase of noncontrolling interest			(5,040)	(5,510)
Intercompany capital contribution			13,284	0
Purchase of treasury shares			0	0
Proceeds from exercises under stock plans			0	0
Purchase of common treasury shares - stock plan exercises			0	0
Net cash flows from financing activities			(58,216)	(143,422)
Effect of exchange rate changes on cash and cash equivalents			(3,354)	(14,425)
Net change in cash and cash equivalents			(57,964)	(145,470)
Cash, cash equivalents, and restricted cash—beginning of year			203,436	404,172
Cash, cash equivalents, and restricted cash—end of period	$ 145,472	$ 258,702	$ 145,472	$ 258,702