Intangible Assets - Schedule of Carrying Amount of Intangible Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Finite And Indefinite Lived Intangible Assets [Line Items]
Finite-lived intangible assets, Gross	$ 507,622	$ 507,107
Finite-lived intangible assets, Accumulated Amortization	(291,007)	(281,554)
Finite-lived intangible assets, Net	216,615	225,553
Intangible assets, Gross	616,926	616,200
Intangible assets, net	325,919	334,646
Customer Relationships [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Finite-lived intangible assets, Gross	366,169	365,777
Finite-lived intangible assets, Accumulated Amortization	(156,458)	(148,679)
Finite-lived intangible assets, Net	209,711	217,098
Technology [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Finite-lived intangible assets, Gross	27,090	27,003
Finite-lived intangible assets, Accumulated Amortization	(26,364)	(26,206)
Finite-lived intangible assets, Net	726	797
Tradenames [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Finite-lived intangible assets, Gross	18,314	18,293
Finite-lived intangible assets, Accumulated Amortization	(16,787)	(16,657)
Finite-lived intangible assets, Net	1,527	1,636
Indefinite-lived intangible assets	109,304	109,093
Backlog [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Finite-lived intangible assets, Gross	95,029	95,014
Finite-lived intangible assets, Accumulated Amortization	(90,783)	(89,427)
Finite-lived intangible assets, Net	4,246	5,587
Other [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Finite-lived intangible assets, Gross	1,020	1,020
Finite-lived intangible assets, Accumulated Amortization	(615)	(585)
Finite-lived intangible assets, Net	$ 405	$ 435