Goodwill, Intangible Assets and Impairment Charges - Additional Information (Details)	3 Months Ended		12 Months Ended
	Apr. 03, 2015 USD ($)	Dec. 31, 2014 USD ($) Tradeshow	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Goodwill And Intangible Assets [Line Items]
Impairment of goodwill and intangible assets		$ 41,442,000	$ 41,442,000
Impairment Charge, Intangible assets			21,867,000
Impairment Charge, Goodwill			$ 19,575,000
Minimum
Goodwill And Intangible Assets [Line Items]
Reporting units in excess of carrying value	20.00%
Vision Technologies
Goodwill And Intangible Assets [Line Items]
Impairment of goodwill and intangible assets	$ 0			$ 0
Number of main tradeshows for the NDS Business | Tradeshow		2
Impairment Charge, Intangible assets		$ 21,800,000
Impairment Charge, Goodwill		$ 19,600,000