Goodwill and Other Intangible Assets - Future Amortization Expense of Other Intangible Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2019	$ 10,820
2020	10,648
2021	10,478
2022	10,418
2023	10,359
Thereafter	59,369
Net Carrying Amount	112,092	$ 114,693
Electronic Systems
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2019	9,419
2020	9,348
2021	9,287
2022	9,288
2023	9,287
Thereafter	55,808
Net Carrying Amount	102,437	111,857
Structural Systems
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2019	1,401
2020	1,300
2021	1,191
2022	1,130
2023	1,072
Thereafter	3,561
Net Carrying Amount	$ 9,655	$ 2,836