Restructuring and Impairment Charges (Restructuring and Impairment Charges) (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restructuring and Impairment
Restructuring charges	$ 397		$ 700
Total Charges for Restructuring and Impairment		$ 3,567	734	$ 0
Advanced Connectivity Solutions | Employee Severance
Restructuring and Impairment
Restructuring charges		1,305	375
Advanced Connectivity Solutions | Asset Impairments
Restructuring and Impairment
Allocated asset impairment charges		161	0
Elastomeric Material Solutions | Employee Severance
Restructuring and Impairment
Restructuring charges		834	176
Elastomeric Material Solutions | Asset Impairments
Restructuring and Impairment
Allocated asset impairment charges		103	0
Power Electronics Solutions | Employee Severance
Restructuring and Impairment
Restructuring charges		621	183
Power Electronics Solutions | Asset Impairments
Restructuring and Impairment
Allocated asset impairment charges		$ 543	$ 0