Discontinued Operations and Divestitures - Loss from Discontinued Operations, Net of Tax (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Discontinued Operations and Disposal Groups [Abstract]
Revenue									$ 14,589	$ 106,869	$ 153,405
(Loss) income from operations of discontinued operations before income tax expense									(925)	4,602	12,214
Income tax (benefit) expense									(171)	2,454	4,951
(Loss) income from operations of discontinued operations operations, net of tax	$ 60	$ (239)	$ (312)	$ (263)	$ (1,130)	$ 453	$ 1,639	$ 1,186	$ (754)	$ 2,148	$ 7,263