Acquisition - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended	1 Months Ended
Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Aug. 01, 2013 Cable Holdings [Member]
Business Acquisition [Line Items]
Cash paid for acquisition, net of cash acquired	$ 6,953	$ 0	$ 6,953	$ 0	$ 6,953

The cash outflow associated with the acquisition of a business, net of the cash acquired from the purchase.

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Investing Activities

-URI http://asc.fasb.org/extlink&oid=6516133

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 13

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3213-108585

Name:	us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration