Revenues and Net Loss of Acquired Entity Since Acquisition Date (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended		1 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012 Alpine Access Inc [Member]
Business Acquisition [Line Items]
Revenues	$ 292,580	$ 318,932	$ 885,878	$ 966,926	$ 10,095
(Loss) from continuing operations before income taxes	(1,935)				(1,935)
(Loss) from continuing operations, net of taxes					$ (1,907)