Fair Value Measurements (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	$ 191,917	$ 398,188
Real Estate Fund investments	667,710	600,786
Deferred Compensation Plan Assets	116,515	105,200
Derivative Assets		11,165
Total assets	976,142	1,115,339
Mandatorily redeemable instruments (included in other liabilities)	55,097	55,011
Interest rate swap (included in other liabilities)	31,882	50,065
Total liabilities	86,979	105,076
Other Partners Ownership Interest In Real Estate Fund (in percentage)	75.00%	75.00%
Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in Partially Owned Entities at Fair Value	83,224	478,041
Real Estate, Net at Fair Value	354,341	189,529
Condominium units (included in other assets)		52,142
Total Assets, Nonrecurring	437,565	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	191,917	398,188
Real Estate Fund investments	0	0
Deferred Compensation Plan Assets	47,733	42,569
Derivative Assets		0
Total assets	239,650	440,757
Mandatorily redeemable instruments (included in other liabilities)	55,097	55,011
Interest rate swap (included in other liabilities)	0	0
Total liabilities	55,097	55,011
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in Partially Owned Entities at Fair Value	0	0
Real Estate, Net at Fair Value	0	0
Condominium units (included in other assets)		0
Total Assets, Nonrecurring	0	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	0	0
Deferred Compensation Plan Assets	0	0
Derivative Assets		11,165
Total assets	0	11,165
Mandatorily redeemable instruments (included in other liabilities)	0	0
Interest rate swap (included in other liabilities)	31,882	50,065
Total liabilities	31,882	50,065
Fair Value Inputs Level 2 Member | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in Partially Owned Entities at Fair Value	0	0
Real Estate, Net at Fair Value	0	0
Condominium units (included in other assets)		0
Total Assets, Nonrecurring	0	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	667,710	600,786
Deferred Compensation Plan Assets	68,782	62,631
Derivative Assets		0
Total assets	736,492	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, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in Partially Owned Entities at Fair Value	83,224	478,041
Real Estate, Net at Fair Value	354,341	189,529
Condominium units (included in other assets)		52,142
Total Assets, Nonrecurring	$ 437,565	$ 719,712