Pensions and Other Postretirement Benefits (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017 USD ($) Plan	Sep. 30, 2017 USD ($)	Jul. 01, 2017 USD ($)	Apr. 01, 2017 USD ($)	Dec. 31, 2016 USD ($)	Oct. 01, 2016 USD ($)	Jul. 02, 2016 USD ($)	Apr. 02, 2016 USD ($)	Dec. 31, 2017 USD ($) Plan	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Amounts recognized in balance sheet associated with retirement benefit plans [Abstract]
Included in other assets	$ 347				$ 248				$ 347	$ 248
Pension and Other Postretirement Defined Benefit Plans, Current Liabilities	(8,503)				(7,479)				(8,503)	(7,479)
Accrued pension and other postretirement costs	(281,701)				(257,789)				(281,701)	(257,789)
Accumulated other comprehensive loss	96,944				88,860				96,944	88,860
Components of actuarial items [Abstract]
Total actuarial items	96,944				88,860				96,944	88,860
Components of net periodic pension cost [Abstract]
Curtailment and settlement losses (gains)	0	$ 0	$ 0	$ 0	79,321	$ 0	$ 0	$ 0	0	79,321	$ 0
Amounts that will be amortized from accumulated other comprehensive loss into net periodic pension cost during next fiscal year	$ 7,300								$ 7,300
Other postretirement benefits [Abstract]
Number of unfunded non-pension postretirement plans | Plan	2								2
Number of European subsidiaries with unfunded non-pension postretirement plans | Plan	2								2
Other retirement obligations [Abstract]
Company's matching expense for 401(k) savings plans									$ 5,843	5,039	5,369
Defined Benefit Pension [Member] | Domestic Plan [Member]
Change in benefit obligation [Roll forward]
Benefit obligation at beginning of year				38,914				274,122	38,914	274,122
Service cost									0	0	0
Interest cost									1,643	11,788	11,657
Plan amendments and initiations									0	0
Transfer from equity affiliate (liabilities)									0	0
Actuarial (gains) losses									1,149	19,916
Benefits paid									(1,789)	(15,625)
Curtailments and settlements									0	(251,287)
Currency translation									0	0
Benefit obligation at end of year	$ 39,917				38,914				39,917	38,914	274,122
Change in plan assets [Roll forward]
Fair value of plan assets at beginning of year				0				258,092	0	258,092
Actual return on plan assets									0	14,068
Transfer from Equity Affiliate (assets)									0	0
Company contributions									1,789	(5,248)
Benefits paid									(1,789)	(15,625)
Curtailments and settlements									0	(251,287)
Currency translation									0	0
Fair value of plan assets at end of year	0				0				0	0	258,092
Funded status at end of year	(39,917)				(38,914)				(39,917)	(38,914)
Amounts recognized in balance sheet associated with retirement benefit plans [Abstract]
Included in other assets	0				0				0	0
Pension and Other Postretirement Defined Benefit Plans, Current Liabilities	(37)				(35)				(37)	(35)
Accrued pension and other postretirement costs	(39,880)				(38,879)				(39,880)	(38,879)
Accumulated other comprehensive loss	7,731				7,313				7,731	7,313
Total	(32,186)				(31,601)				(32,186)	(31,601)
Components of actuarial items [Abstract]
Unrecognized net actuarial loss (gain)	6,804				6,241				6,804	6,241
Unamortized prior service (credit) cost	927				1,072				927	1,072
Total actuarial items	7,731				7,313				7,731	7,313
Projected and accumulated benefit obligations [Abstract]
Accumulated benefit obligation, all plans	39,917				38,914				39,917	38,914
Plans for which the accumulated benefit obligation exceeds plan assets [Abstract]
Projected benefit obligation	39,917				38,914				39,917	38,914
Accumulated benefit obligation	39,917				38,914				39,917	38,914
Fair value of plan assets	$ 0				$ 0				0	0
Components of net periodic pension cost [Abstract]
Net service cost									0	0	0
Interest cost									1,643	11,788	11,657
Expected return on plan assets									0	(11,302)	(13,566)
Amortization of actuarial losses									587	6,513	8,175
Amortization of prior service (credit) cost									144	144	64
Curtailment and settlement losses (gains)									0	79,321	0
Net periodic benefit cost									$ 2,374	$ 86,464	6,330
Weighted average assumptions used to calculate benefit obligations [Abstract]
Discount rate (in hundredths)	3.75%				4.25%				3.75%	4.25%
Rate of compensation increase (in hundredths)	0.00%				0.00%				0.00%	0.00%
Weighted average assumptions used calculating net periodic benefit cost [Abstract]
Discount rate (in hundredths)									4.25%	4.50%
Rate of compensation increase (in hundredths)									0.00%	0.00%
Expected return on plan assets (in hundredths)									0.00%	4.50%
Estimated future benefit payments [Abstract]
2018	$ 1,802								$ 1,802
2019	1,809								1,809
2020	7,880								7,880
2021	3,038								3,038
2022	3,006								3,006
2023-2027	16,904								16,904
Defined Benefit Pension [Member] | Foreign Plan [Member]
Change in benefit obligation [Roll forward]
Benefit obligation at beginning of year				266,427				260,554	266,427	$ 260,554
Service cost									3,725	3,291	3,265
Interest cost									4,866	5,475	5,636
Plan amendments and initiations									686	291
Transfer from equity affiliate (liabilities)									0	358
Actuarial (gains) losses									3,019	17,202
Benefits paid									(17,921)	(12,607)
Curtailments and settlements									0	0
Currency translation									30,360	(8,137)
Benefit obligation at end of year	291,162				$ 266,427				291,162	266,427	260,554
Change in plan assets [Roll forward]
Fair value of plan assets at beginning of year				66,090				51,263	66,090	51,263
Actual return on plan assets									1,608	2,588
Transfer from Equity Affiliate (assets)									0	358
Company contributions									16,120	27,311
Benefits paid									(17,921)	(12,607)
Curtailments and settlements									0	0
Currency translation									4,708	(2,823)
Fair value of plan assets at end of year	70,605				66,090				70,605	66,090	51,263
Funded status at end of year	(220,557)				(200,337)				(220,557)	(200,337)
Amounts recognized in balance sheet associated with retirement benefit plans [Abstract]
Included in other assets	347				248				347	248
Pension and Other Postretirement Defined Benefit Plans, Current Liabilities	(7,308)				(6,405)				(7,308)	(6,405)
Accrued pension and other postretirement costs	(213,596)				(194,180)				(213,596)	(194,180)
Accumulated other comprehensive loss	88,398				82,360				88,398	82,360
Total	(132,159)				(117,977)				(132,159)	(117,977)
Components of actuarial items [Abstract]
Unrecognized net actuarial loss (gain)	87,896				82,360				87,896	82,360
Unamortized prior service (credit) cost	502				0				502	0
Total actuarial items	88,398				82,360				88,398	82,360
Projected and accumulated benefit obligations [Abstract]
Accumulated benefit obligation, all plans	270,914				247,838				270,914	247,838
Plans for which the accumulated benefit obligation exceeds plan assets [Abstract]
Projected benefit obligation	277,615				253,390				277,615	253,390
Accumulated benefit obligation	262,779				240,793				262,779	240,793
Fair value of plan assets	$ 57,727				$ 56,649				57,727	56,649
Components of net periodic pension cost [Abstract]
Net service cost									3,725	3,291	3,265
Interest cost									4,866	5,475	5,636
Expected return on plan assets									(2,072)	(2,117)	(1,798)
Amortization of actuarial losses									6,179	4,733	5,131
Amortization of prior service (credit) cost									150	261	(282)
Curtailment and settlement losses (gains)									1,360	841	452
Net periodic benefit cost									$ 14,208	$ 12,484	12,404
Weighted average assumptions used to calculate benefit obligations [Abstract]
Discount rate (in hundredths)	1.80%				1.76%				1.80%	1.76%
Rate of compensation increase (in hundredths)	2.10%				2.12%				2.10%	2.12%
Weighted average assumptions used calculating net periodic benefit cost [Abstract]
Discount rate (in hundredths)									1.76%	2.30%
Rate of compensation increase (in hundredths)									2.12%	1.99%
Expected return on plan assets (in hundredths)									2.90%	3.38%
Estimated future benefit payments [Abstract]
2018	$ 17,397								$ 17,397
2019	16,418								16,418
2020	15,958								15,958
2021	15,773								15,773
2022	17,962								17,962
2023-2027	84,438								84,438
Other Postretirement Benefits [Member] | Domestic Plan [Member]
Change in benefit obligation [Roll forward]
Benefit obligation at beginning of year				7,647				7,909	7,647	$ 7,909
Service cost									131	126	121
Interest cost									311	340	333
Actuarial (gains) losses									257	(25)
Benefits paid									(713)	(703)
Curtailments and settlements									0	0
Currency translation									0	0
Benefit obligation at end of year	7,633				$ 7,647				7,633	7,647	7,909
Change in plan assets [Roll forward]
Fair value of plan assets at beginning of year				0					0
Benefits paid									(713)	(703)
Fair value of plan assets at end of year	0				0				0	0
Funded status at end of year	(7,633)				(7,647)				(7,633)	(7,647)
Amounts recognized in balance sheet associated with retirement benefit plans [Abstract]
Pension and Other Postretirement Defined Benefit Plans, Current Liabilities	(705)				(717)				(705)	(717)
Accrued pension and other postretirement costs	(6,928)				(6,930)				(6,928)	(6,930)
Accumulated other comprehensive loss	(1,101)				(2,287)				(1,101)	(2,287)
Total	(8,734)				(9,934)				(8,734)	(9,934)
Components of actuarial items [Abstract]
Unrecognized net actuarial loss (gain)	(953)				(1,303)				(953)	(1,303)
Unamortized prior service (credit) cost	(148)				(984)				(148)	(984)
Total actuarial items	$ (1,101)				$ (2,287)				(1,101)	(2,287)
Components of net periodic pension cost [Abstract]
Net service cost									131	126	121
Interest cost									311	340	333
Amortization of actuarial losses									(93)	(30)	90
Amortization of prior service (credit) cost									(837)	(837)	(837)
Net periodic benefit cost									$ (488)	$ (401)	(293)
Weighted average assumptions used to calculate benefit obligations [Abstract]
Discount rate (in hundredths)	3.75%				4.25%				3.75%	4.25%
Rate of compensation increase (in hundredths)	0.00%				0.00%				0.00%	0.00%
Weighted average assumptions used calculating net periodic benefit cost [Abstract]
Discount rate (in hundredths)									4.25%	4.50%
Rate of compensation increase (in hundredths)									0.00%	0.00%
Estimated future benefit payments [Abstract]
2018	$ 705								$ 705
2019	703								703
2020	685								685
2021	660								660
2022	632								632
2023-2027	2,472								2,472
Other Postretirement Benefits [Member] | Foreign Plan [Member]
Change in benefit obligation [Roll forward]
Benefit obligation at beginning of year				6,625				$ 6,488	6,625	$ 6,488
Service cost									273	268	273
Interest cost									103	143	147
Actuarial (gains) losses									312	171
Benefits paid									(349)	(221)
Curtailments and settlements									0	0
Currency translation									934	(224)
Benefit obligation at end of year	7,898				$ 6,625				7,898	6,625	6,488
Change in plan assets [Roll forward]
Fair value of plan assets at beginning of year				$ 0					0
Benefits paid									(349)	(221)
Fair value of plan assets at end of year	0				0				0	0
Funded status at end of year	(7,898)				(6,625)				(7,898)	(6,625)
Amounts recognized in balance sheet associated with retirement benefit plans [Abstract]
Pension and Other Postretirement Defined Benefit Plans, Current Liabilities	(453)				(322)				(453)	(322)
Accrued pension and other postretirement costs	(7,445)				(6,303)				(7,445)	(6,303)
Accumulated other comprehensive loss	1,916				1,474				1,916	1,474
Total	(5,982)				(5,151)				(5,982)	(5,151)
Components of actuarial items [Abstract]
Unrecognized net actuarial loss (gain)	1,916				1,474				1,916	1,474
Unamortized prior service (credit) cost	0				0				0	0
Total actuarial items	$ 1,916				$ 1,474				1,916	1,474
Components of net periodic pension cost [Abstract]
Net service cost									273	268	273
Interest cost									103	143	147
Amortization of actuarial losses									76	68	76
Amortization of prior service (credit) cost									0	0	0
Net periodic benefit cost									$ 452	$ 479	$ 496
Weighted average assumptions used to calculate benefit obligations [Abstract]
Discount rate (in hundredths)	1.50%				1.50%				1.50%	1.50%
Rate of compensation increase (in hundredths)	2.88%				2.58%				2.88%	2.58%
Weighted average assumptions used calculating net periodic benefit cost [Abstract]
Discount rate (in hundredths)									1.50%	2.31%
Rate of compensation increase (in hundredths)									2.58%	2.69%
Estimated future benefit payments [Abstract]
2018	$ 453								$ 453
2019	338								338
2020	592								592
2021	494								494
2022	725								725
2023-2027	3,161								3,161
Other Retirement Obligations [Member]
Amounts recognized in balance sheet associated with retirement benefit plans [Abstract]
Accrued pension and other postretirement costs	(13,852)				$ (11,497)				(13,852)	$ (11,497)
Deferred Compensation [Member]
Defined benefit pension plans [Abstract]
Assets held in trust	18,958				16,632				18,958	16,632
Non-qualified Pension Plans [Member]
Defined benefit pension plans [Abstract]
Assets held in trust	24,505				22,896				24,505	22,896
Dr. Felix Zandman [Member] | Non-qualified Pension Plans [Member]
Defined benefit pension plans [Abstract]
Assets held in trust	$ 1,789				$ 2,389				1,789	$ 2,389
Deferred compensation arrangement, annual retirement benefit to surviving spouse									$ 614