Fair Value Measurements (Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Financial Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis
Real estate fund investments	$ 7,730	$ 3,739
Real estate fund investments
Financial Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis
Real estate fund investments	7,730	3,739
Recurring
Financial Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis
Real estate fund investments	7,730	3,739
Deferred compensation plan assets (included in restricted cash and other assets)	110,174	105,564
Loans receivable (included in investments in partially owned entities and in other assets)	50,182	47,743
Interest rate swaps and caps (included in other assets)	18,929	17
Total assets	187,015	157,063
Mandatorily redeemable instruments (included in other liabilities)	49,659	50,002
Interest rate swaps (included in other liabilities)	32,837	66,033
Total liabilities	82,496	116,035
Recurring | Level 1
Financial Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis
Real estate fund investments	0	0
Deferred compensation plan assets (included in restricted cash and other assets)	65,158	65,636
Loans receivable (included in investments in partially owned entities and in other assets)	0	0
Interest rate swaps and caps (included in other assets)	0	0
Total assets	65,158	65,636
Mandatorily redeemable instruments (included in other liabilities)	49,659	50,002
Interest rate swaps (included in other liabilities)	0	0
Total liabilities	49,659	50,002
Recurring | Level 2
Financial Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis
Real estate fund investments	0	0
Deferred compensation plan assets (included in restricted cash and other assets)	0	0
Loans receivable (included in investments in partially owned entities and in other assets)	0	0
Interest rate swaps and caps (included in other assets)	18,929	17
Total assets	18,929	17
Mandatorily redeemable instruments (included in other liabilities)	0	0
Interest rate swaps (included in other liabilities)	32,837	66,033
Total liabilities	32,837	66,033
Recurring | Level 3
Financial Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis
Real estate fund investments	7,730	3,739
Deferred compensation plan assets (included in restricted cash and other assets)	45,016	39,928
Loans receivable (included in investments in partially owned entities and in other assets)	50,182	47,743
Interest rate swaps and caps (included in other assets)	0	0
Total assets	102,928	91,410
Mandatorily redeemable instruments (included in other liabilities)	0	0
Interest rate swaps (included in other liabilities)	0	0
Total liabilities	0	0
Recurring | Level 3 | Real estate fund investments
Financial Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis
Real estate fund investments	7,730
Restricted Cash | Recurring
Financial Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis
Deferred compensation plan assets (included in restricted cash and other assets)	9,104	10,813
Other Assets | Recurring
Financial Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis
Deferred compensation plan assets (included in restricted cash and other assets)	101,070	94,751
Loans receivable (included in investments in partially owned entities and in other assets)	3,738	4,735
Partially Owned Properties | Recurring
Financial Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis
Loans receivable (included in investments in partially owned entities and in other assets)	$ 46,444	$ 43,008