Income Taxes (Details 3) (USD $) In Thousands, unless otherwise specified	Jan. 31, 2013		Jan. 31, 2012
Net Deferred Tax Liability
Deferred tax liabilities	$ 1,832,038		$ 1,802,841
Deferred tax assets	1,410,914		1,425,131
Less: valuation allowance	(53,282)	[1]	(55,330)	[1]
Net deferred tax assets	1,357,632		1,369,801
Net deferred tax liability	$ 474,406		$ 433,040

[1] The valuation allowance is related to state net operating losses and bonus depreciation, general business credits and charitable contributions.