Fair Value Measurements (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	$ 402,935	$ 398,188
Real Estate Fund investments (75% of which is attributable to noncontrolling interests)	622,124	600,786
Deferred compensation plan assets (included in other assets)	111,093	105,200
J.C. Penney derivative position (included in other assets)	10,687	11,165
Total assets	1,146,839	1,115,339
Mandatorily redeemable instruments (included in other liabilities)	55,073	55,011
Interest rate swap (included in other liabilities)	35,505	50,065
Total liabilities	90,578	105,076
Fair Value, Measurements, Nonrecurring [Member]
Fair Value Measurements On Nonrecurring Basis [Abstract]
Investment in Toys"R" Us		478,041
Real estate assets		189,529
Condominium units (included in other assets)		52,142
Total Assets, Nonrecurring		719,712
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	402,935	398,188
Real Estate Fund investments (75% of which is attributable to noncontrolling interests)	0	0
Deferred compensation plan assets (included in other assets)	44,591	42,569
J.C. Penney derivative position (included in other assets)	0	0
Total assets	447,526	440,757
Mandatorily redeemable instruments (included in other liabilities)	55,073	55,011
Interest rate swap (included in other liabilities)	0	0
Total liabilities	55,073	55,011
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value Measurements On Nonrecurring Basis [Abstract]
Investment in Toys"R" Us		0
Real estate assets		0
Condominium units (included in other assets)		0
Total Assets, Nonrecurring		0
Fair Value Inputs Level 2 Member | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	0	0
Real Estate Fund investments (75% of which is attributable to noncontrolling interests)	0	0
Deferred compensation plan assets (included in other assets)	0	0
J.C. Penney derivative position (included in other assets)	10,687	11,165
Total assets	10,687	11,165
Mandatorily redeemable instruments (included in other liabilities)	0	0
Interest rate swap (included in other liabilities)	35,505	50,065
Total liabilities	35,505	50,065
Fair Value Inputs Level 2 Member | Fair Value, Measurements, Nonrecurring [Member]
Fair Value Measurements On Nonrecurring Basis [Abstract]
Investment in Toys"R" Us		0
Real estate assets		0
Condominium units (included in other assets)		0
Total Assets, Nonrecurring		0
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	0	0
Real Estate Fund investments (75% of which is attributable to noncontrolling interests)	622,124	600,786
Deferred compensation plan assets (included in other assets)	66,502	62,631
J.C. Penney derivative position (included in other assets)	0	0
Total assets	688,626	663,417
Mandatorily redeemable instruments (included in other liabilities)	0	0
Interest rate swap (included in other liabilities)	0	0
Total liabilities	0	0
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value Measurements On Nonrecurring Basis [Abstract]
Investment in Toys"R" Us		478,041
Real estate assets		189,529
Condominium units (included in other assets)		52,142
Total Assets, Nonrecurring		$ 719,712