Goodwill and Other Intangible Assets - Carrying Amount of Other Intangible Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 161,445	$ 161,445
Accumulated Amortization	59,872	50,824
Net Carrying Amount	$ 101,573	110,621
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Estimated useful life of intangible assets (in years)	18 years
Gross Carrying Amount	$ 159,200	159,200
Accumulated Amortization	58,352	49,463
Net Carrying Amount	$ 100,848	109,737
Contract renewal
Finite-Lived Intangible Assets [Line Items]
Estimated useful life of intangible assets (in years)	14 years
Gross Carrying Amount	$ 1,845	1,845
Accumulated Amortization	1,362	1,230
Net Carrying Amount	$ 483	615
Technology
Finite-Lived Intangible Assets [Line Items]
Estimated useful life of intangible assets (in years)	15 years
Gross Carrying Amount	$ 400	400
Accumulated Amortization	158	131
Net Carrying Amount	242	269
Structural Systems
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	19,300	19,300
Accumulated Amortization	15,555	14,433
Net Carrying Amount	3,745	4,867
Electronic Systems
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	142,145	142,145
Accumulated Amortization	44,317	36,391
Net Carrying Amount	$ 97,828	$ 105,754