Fair Value Measurements (Details 2) (Fair value measurement, recurring basis [Member], USD $)					6 Months Ended
	Jul. 31, 2013	Jul. 31, 2012	Jul. 31, 2013 Fair Value, Inputs, Level 3 [Member]	Jul. 31, 2012 Fair Value, Inputs, Level 3 [Member]	Jul. 31, 2013 Credit valuation adjustment of interest rate swap [Member] Fair Value, Inputs, Level 3 [Member]	Jul. 31, 2013 Total Return Swap [Member] Fair Value, Inputs, Level 3 [Member]	Jul. 31, 2013 Total Return Swap [Member] Discount rate [Member] Fair Value, Inputs, Level 3 [Member]		Jul. 31, 2013 Total Return Swap [Member] Capitalization rate [Member] Fair Value, Inputs, Level 3 [Member]		Jul. 31, 2013 Fair value adjustment to the borrowings subject to TRS [Member] Fair Value, Inputs, Level 3 [Member]	Jul. 31, 2013 Fair value adjustment to the borrowings subject to TRS [Member] Discount rate [Member] Fair Value, Inputs, Level 3 [Member]		Jul. 31, 2013 Fair value adjustment to the borrowings subject to TRS [Member] Capitalization rate [Member] Fair Value, Inputs, Level 3 [Member]		Jul. 31, 2013 Redeemable Noncontrolling Interest [Member] Fair Value, Inputs, Level 3 [Member]
Fair value of financial instruments measured on a recurring basis
Credit valuation adjustment of interest rate swap					$ 8,706,000
Fair value measurement of total return swap						(13,156,000)
Fair value adjustment to borrowings subject to total rate of return swap											8,724,000
Redeemable noncontrolling interest	$ (231,434,000)	$ (239,136,000)	$ (231,434,000)	$ (239,136,000)												$ (231,434,000)
Fair value valuation technique credit valuation adjustment of interest rate swap					Potential future exposure
Fair value valuation technique of total return swap						Bond quote
Fair value valuation technique adjustment to borrowings subject to total rate of return swap											Bond quote
Fair value valuation technique of redeemable noncontrolling interest																Discounted cash flows
Fair value unobservable input credit valuation adjustment of interest rate swap					Credit spread
Fair value unobservable input of total return swap						Discount rate
Fair Value Unobservable Input Total Return Swap						Capitalization rate
Fair value unobservable input adjustment to borrowings subject to total rate of return swap											Discount rate
Fair value unobservable input adjustment to borrowings subject total rate of return swap											Capitalization rate
Fair value unobservable input redeemable noncontrolling interest																Discount rate
Percentage of input values credit valuation adjustment of interest rate swap					4.25%
Input Values Total Rate Of Return Swap							N/A	[1]	N/A	[1]
Input values of fair value adjustment to the borrowing subject total rate of return swap												N/A	[1]	N/A	[1]
Percentage of input values redeemable noncontrolling interest																9.30%

[1] The Company does not have access to certain significant unobservable inputs used by these third parties to determine these fair values.