Fair Value Measurements (Details 1) (USD $)	3 Months Ended
	Apr. 30, 2013	Apr. 30, 2012
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	$ (360,828,000)	$ (378,285,000)
Loss attributable to redeemable noncontrolling interest	6,499,000	1,691,000
Total realized and unrealized gains (losses):
Included in earnings	(1,606,000)	4,303,000
Included in other comprehensive income	335,000	6,786,000
Included in additional paid-in capital	(6,305,000)	(2,980,000)
Ending Balance	(361,905,000)	(368,485,000)
Redeemable Noncontrolling Interest [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	(239,136,000)	(229,149,000)
Loss attributable to redeemable noncontrolling interest	6,499,000	1,691,000
Total realized and unrealized gains (losses):
Included in earnings	0	0
Included in other comprehensive income	0	0
Included in additional paid-in capital	(6,305,000)	(2,980,000)
Ending Balance	(238,942,000)	(230,438,000)
Interest Rate Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	(126,506,000)	(143,303,000)
Loss attributable to redeemable noncontrolling interest	0	0
Total realized and unrealized gains (losses):
Included in earnings	0	0
Included in other comprehensive income	335,000	6,786,000
Included in additional paid-in capital	0	0
Ending Balance	(126,171,000)	(136,517,000)
Net TRS [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	(5,136,000)	(15,013,000)
Loss attributable to redeemable noncontrolling interest	0	0
Total realized and unrealized gains (losses):
Included in earnings	(1,700,000)	4,158,000
Included in other comprehensive income	0	0
Included in additional paid-in capital	0	0
Ending Balance	(6,836,000)	(10,855,000)
Fair Value Adjustment to the Borrowings Subject to TRS [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	9,950,000	9,180,000
Loss attributable to redeemable noncontrolling interest	0	0
Total realized and unrealized gains (losses):
Included in earnings	94,000	145,000
Included in other comprehensive income	0	0
Included in additional paid-in capital	0	0
Ending Balance	10,044,000	9,325,000
TRS Related [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	4,814,000	(5,833,000)
Loss attributable to redeemable noncontrolling interest	0	0
Total realized and unrealized gains (losses):
Included in earnings	(1,606,000)	4,303,000
Included in other comprehensive income	0	0
Included in additional paid-in capital	0	0
Ending Balance	$ 3,208,000	$ (1,530,000)