Segment and Geographic Information - Summarized Financial Information by Business Segment (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 28, 2019 USD ($)	Jun. 29, 2018 USD ($)	Jun. 28, 2019 USD ($) segment	Jun. 29, 2018 USD ($)
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Number of operating segments | segment			2
Net sales	$ 174,712	$ 178,606	$ 341,146	$ 358,001
Net gain on sale of assets	0	1,528	65	1,589
Operating income	10,575	7,226	22,944	15,842
Interest expense, net	5,236	5,000	10,537	10,323
Non-service pension and post retirement benefit income	(100)	(3,039)	(199)	(6,068)
Other (income) expense, net	(463)	364	(552)	22
Earnings from continuing operations before income taxes	5,902	4,901	13,158	11,565
Income tax (benefit) expense	(487)	123	947	1,817
Earnings from continuing operations	6,389	4,778	12,211	9,748
Earnings from discontinued operations, net of tax	7,077	10,316	15,380	19,412
Net earnings	13,466	15,094	27,591	29,160
Aerospace
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net sales	174,712	178,606	341,146	358,001
Operating segments | Aerospace
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net sales	174,712	178,606	341,146	358,001
Operating income	24,598	22,741	51,210	45,403
Reconciling item
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net gain on sale of assets	0	1,528	65	1,589
Corporate
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating income	$ (14,023)	$ (17,043)	$ (28,331)	$ (31,150)