Goodwill and Amortizable Intangible Assets - Additional Information (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 133,031	$ 133,031
Gross Carrying Amount	41,579
Amortizable intangible assets, Accumulated Amortization	$ 25,496
Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Useful Life (In Years)	2 years
Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Useful Life (In Years)	10 years