Fair Value Measurements (Details 1) (USD $)	6 Months Ended
	Jul. 31, 2013	Jul. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning	$ (360,828,000)	$ (378,285,000)
Loss attributable to redeemable noncontrolling interest	11,787,000	4,308,000
Total realized and unrealized gains (losses):
Included in earnings	(9,246,000)	7,652,000
Included in other comprehensive income	19,015,000	1,463,000
Included in additional paid-in capital	(4,085,000)	(7,266,000)
Balance, ending	(343,357,000)	(372,128,000)
Redeemable Noncontrolling Interest [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning	(239,136,000)	(229,149,000)
Loss attributable to redeemable noncontrolling interest	11,787,000	4,308,000
Total realized and unrealized gains (losses):
Included in earnings	0	0
Included in other comprehensive income	0	0
Included in additional paid-in capital	(4,085,000)	(7,266,000)
Balance, ending	(231,434,000)	(232,107,000)
Interest Rate Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning	(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	19,015,000	1,463,000
Included in additional paid-in capital	0	0
Balance, ending	(107,491,000)	(141,840,000)
Net TRS [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning	(5,136,000)	(15,013,000)
Loss attributable to redeemable noncontrolling interest	0	0
Total realized and unrealized gains (losses):
Included in earnings	(8,020,000)	7,282,000
Included in other comprehensive income	0	0
Included in additional paid-in capital	0	0
Balance, ending	(13,156,000)	(7,731,000)
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]
Balance, beginning	9,950,000	9,180,000
Loss attributable to redeemable noncontrolling interest	0	0
Total realized and unrealized gains (losses):
Included in earnings	(1,226,000)	370,000
Included in other comprehensive income	0	0
Included in additional paid-in capital	0	0
Balance, ending	8,724,000	9,550,000
TRS Related [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning	4,814,000	(5,833,000)
Loss attributable to redeemable noncontrolling interest	0	0
Total realized and unrealized gains (losses):
Included in earnings	(9,246,000)	7,652,000
Included in other comprehensive income	0	0
Included in additional paid-in capital	0	0
Balance, ending	$ (4,432,000)	$ 1,819,000