Significant Accounting Policies Update (Details) - USD ($) $ in Thousands		3 Months Ended
	Jan. 01, 2018	Mar. 30, 2018	Mar. 31, 2017	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings	$ (578,293)	$ (586,778)		$ (587,877)
Net sales		463,327	$ 435,941
Operating income		20,724	13,489
Gross profit		134,107	124,346
Contract liabilities, noncurrent portion	689	81,708		$ 0
Cost to Fulfill Contract
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Capitalized contract cost		9,800
Costs to Obtain Contract
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Capitalized contract cost		6,100
Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings	9,584	(2,219)
Net sales		(43,501)
Operating income		(9,666)
Gross profit		(10,243)
Contract liabilities, noncurrent portion	689	(81,708)
Aerospace
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales		1,600
Aerospace | Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings	32,500
Write-off of inventory	32,500
Net sales	62,300
Operating income			$ 1,000
Gross profit	$ 20,200
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-03-30
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected revenue from backlog		563,200
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: (nil)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected revenue from backlog		$ 948,900