Goodwill and Other Intangible Assets - Carrying Amount of Goodwill (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Goodwill [Line Items]
Gross goodwill		$ 199,157
Accumulated goodwill impairment		(81,722)
Goodwill [Roll Forward]
Goodwill, beginning balance	$ 117,435
Goodwill, Acquired During Period	18,622
Goodwill, ending balance	136,057
Electronic Systems
Goodwill [Line Items]
Gross goodwill		199,157
Accumulated goodwill impairment		(81,722)
Goodwill [Roll Forward]
Goodwill, beginning balance	117,435
Goodwill, Acquired During Period	0
Goodwill, ending balance	117,435
Structural Systems
Goodwill [Line Items]
Gross goodwill		0
Accumulated goodwill impairment		$ 0
Goodwill [Roll Forward]
Goodwill, beginning balance	0
Goodwill, Acquired During Period	18,622
Goodwill, ending balance	$ 18,622