Discontinued Operations - Additional Information (Detail) (USD $)	12 Months Ended	1 Months Ended
	Dec. 31, 2011	Jan. 27, 2011 Universal Wireline, Inc.	Dec. 31, 2010 Universal Wireline, Inc.
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net cash provided by investing activities of discontinued operations	$ 25,500,000	$ 25,500,000
Impairment of the assets to be disposed			$ 2,200,000