Business Combinations - Additional Information (Detail) $ in Thousands, € in Millions				9 Months Ended
	Apr. 01, 2019 USD ($)	Feb. 28, 2019 USD ($)	Feb. 28, 2019 EUR (€)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2019 USD ($)	Feb. 28, 2019 EUR (€)	Dec. 31, 2018 USD ($)
Business Acquisition [Line Items]
Payments of business, net of cash acquired				$ 18,894	$ 0
Goodwill				25,278				$ 15,621
Intangibles - net				$ 15,216				$ 8,458
SubCon [Member]
Business Acquisition [Line Items]
Business acquisition, percentage of voting interests acquired		100.00%					100.00%
Total purchase price		$ 10,200
Payments of business, net of cash acquired		1,800
Goodwill		7,000
Intangibles - net		$ 4,700
Useful lives		15 years	15 years
Purchase price estimated liability | €							€ 0.9
Potential maximum payment | €			€ 4.0
Remeasurement period		4 years	4 years
SubCon [Member] | Other Noncurrent Liabilities [Member]
Business Acquisition [Line Items]
Business combination earnout liability		$ 900
MICOS Telecom [Member]
Business Acquisition [Line Items]
Total purchase price	$ 8,800
Payments of business, net of cash acquired	500
Goodwill	3,400
Intangibles - net	$ 3,500
Useful lives	15 years
Business combination intangible assets included in goodwill						$ 3,500
Preliminary purchase price of plant and equipment	$ 1,900
MICOS Telecom [Member] | Other Noncurrent Liabilities [Member]
Business Acquisition [Line Items]
Business combination hold-back liability	$ 1,500
Business combination hold-back liability payable term	2 years