Discontinued Operations - Financial Results of Discontinued Operations (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2011
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income tax benefit (expense)	$ (16,178)	$ (395)	$ 1,028
Net (loss) income from discontinued operations	(25,076)	(53)	2,263
Energy [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues	8,520	20,388	25,754
(Loss) income before income taxes	(41,254)	(448)	3,291
Income tax benefit (expense)	16,178	395	(1,028)
Net (loss) income from discontinued operations	$ (25,076)	$ (53)	$ 2,263