Acquisitions - Summary of Estimated Fair Values Allocated to Major Classes of Assets Acquired and Liabilities Assumed (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Business Acquisition [Line Items]
Goodwill	$ 7,290us-gaap_GoodwillGross	$ 3,958us-gaap_GoodwillGross
Cable Holdings [Member] \| Assets Acquired [Member]
Business Acquisition [Line Items]
Accounts receivable and other current assets	1,110
Furniture and equipment	480
Identifiable intangible assets	2,390
Goodwill	3,958
Cable Holdings [Member] \| Liabilities Assumed [Member]
Business Acquisition [Line Items]
Accounts payable and other liabilities	788
Ascolta [Member] \| Assets Acquired [Member]
Business Acquisition [Line Items]
Accounts receivable and other current assets	849
Furniture and equipment	370
Identifiable intangible assets	1,670
Goodwill	3,332
Ascolta [Member] \| Liabilities Assumed [Member]
Business Acquisition [Line Items]
Other liabilities	$ 1,001

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Amount due from customers or clients for goods or services, including trade receivables, that have been delivered or sold in the normal course of business, and amounts due from others, including related parties expected to be converted to cash, sold or exchanged within one year or the normal operating cycle, if longer, acquired at the acquisition date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6910749&loc=d3e4845-128472

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- Definition

Amount of liabilities incurred for goods and services received that are used in an entity's business and related party payables, assumed at the acquisition date.

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- Definition

Amount of other liabilities due within one year or within the normal operating cycle, if longer, assumed at the acquisition date.

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- Definition

Amount of tangible personal property used to produce goods and services, including, but is not limited to, tools, dies and molds, computer and office equipment, acquired at the acquisition date.

+ References

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- Definition

Amount of intangible assets, excluding goodwill, acquired at the acquisition date.

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- Definition

Amount before 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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (a,h)

-URI http://asc.fasb.org/extlink&oid=14024403&loc=d3e13816-109267

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