Summary of Significant Accounting Policies - Assets Held For Sale (Details) - USD ($) $ in Thousands			3 Months Ended
	Mar. 25, 2016	Jan. 22, 2016	Apr. 02, 2016	Dec. 31, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on divestiture			$ 18,800
Assets
Total current assets			0	$ 41,636
Assets Disposed of by Sale | Electronic Systems | Pittsburgh, Pennsylvania Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration received		$ 38,500
Gain on divestiture		18,300
Transaction costs		200
Assets
Total Assets		24,000
Liabilities
Total Liabilities		$ 4,000
Assets Disposed of by Sale | Electronic Systems | Miltec Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration received	$ 14,600
Gain on divestiture	500
Transaction costs	1,300
Assets
Total Assets	15,400
Liabilities
Total Liabilities	$ 2,600
Assets Held For Sale | Electronic Systems
Assets
Accounts receivable (less allowance for doubtful accounts of zero and $24 at April 2, 2016 and December 31, 2015, respectively)			0	9,395
Allowance for doubtful accounts			0	24
Inventory			0	6,453
Deferred income taxes			0	1,246
Other current assets			0	3,315
Total current assets			0	20,409
Property and equipment, net of accumulated depreciation of zero and $8,509 at April 2, 2016 and December 31, 2015, respectively			0	1,941
Accumulated depreciation			0	8,509
Goodwill			0	17,772
Other intangible assets			0	1,514
Total Assets			0	41,636
Liabilities
Accounts payable			0	4,836
Accrued liabilities			0	1,944
Total Liabilities			$ 0	$ 6,780