Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Amount of liability recognized arising from contingent consideration in a business combination.

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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Fair Value Measurements - Fair Value Measurements on a Recurring and Non-Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Non-recurring basis:
Goodwill	$ 45,968us-gaap_Goodwill	$ 48,900us-gaap_Goodwill	$ 63,410us-gaap_Goodwill
Recurring Basis [Member]
Fair value measurements on a recurring and non-recurring basis
Contingent Liability	(477)
Non-Recurring Basis [Member]
Non-recurring basis:
Goodwill		48,900
Money Market Funds [Member] \| Recurring Basis [Member]
Fair value measurements on a recurring and non-recurring basis
Fair value disclosure of assets	0	869
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Recurring Basis [Member]
Fair value measurements on a recurring and non-recurring basis
Contingent Liability	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Non-Recurring Basis [Member]
Non-recurring basis:
Goodwill		0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Money Market Funds [Member] \| Recurring Basis [Member]
Fair value measurements on a recurring and non-recurring basis
Fair value disclosure of assets	0	869
Significant Other Observable Inputs (Level 2) [Member] \| Recurring Basis [Member]
Fair value measurements on a recurring and non-recurring basis
Contingent Liability	0
Significant Other Observable Inputs (Level 2) [Member] \| Non-Recurring Basis [Member]
Non-recurring basis:
Goodwill		0
Significant Other Observable Inputs (Level 2) [Member] \| Money Market Funds [Member] \| Recurring Basis [Member]
Fair value measurements on a recurring and non-recurring basis
Fair value disclosure of assets	0	0
Significant Unobservable Inputs (Level 3) [Member] \| Recurring Basis [Member]
Fair value measurements on a recurring and non-recurring basis
Contingent Liability	(477)
Significant Unobservable Inputs (Level 3) [Member] \| Non-Recurring Basis [Member]
Non-recurring basis:
Goodwill		48,900
Significant Unobservable Inputs (Level 3) [Member] \| Money Market Funds [Member] \| Recurring Basis [Member]
Fair value measurements on a recurring and non-recurring basis
Fair value disclosure of assets	$ 0	$ 0