Fair Value Measurements (Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Financial Assets and Liabilities Measured at Fair Value on a Recurring and Nonrecurring Basis
Proceeds from maturities of U.S. Treasury bills	$ 468,598	$ 349,461
Investments in U.S. Treasury bills
Financial Assets and Liabilities Measured at Fair Value on a Recurring and Nonrecurring Basis
Proceeds from maturities of U.S. Treasury bills	477,000
Recurring
Financial Assets and Liabilities Measured at Fair Value on a Recurring and Nonrecurring Basis
Deferred compensation plan assets (included in restricted cash and other assets)	100,486		$ 96,322
Loans receivable (included in investments in partially owned entities and in other assets)	57,841		54,397
Interest rate swaps and caps (included in other assets)	260,747		183,804
Total assets	419,074		806,485
Mandatorily redeemable instruments (included in other liabilities)	49,383		49,383
Recurring | Investments in U.S. Treasury bills
Financial Assets and Liabilities Measured at Fair Value on a Recurring and Nonrecurring Basis
Investments in U.S. Treasury bills			471,962
Recurring | Level 1
Financial Assets and Liabilities Measured at Fair Value on a Recurring and Nonrecurring Basis
Deferred compensation plan assets (included in restricted cash and other assets)	54,799		57,406
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	54,799		529,368
Mandatorily redeemable instruments (included in other liabilities)	49,383		49,383
Recurring | Level 1 | Investments in U.S. Treasury bills
Financial Assets and Liabilities Measured at Fair Value on a Recurring and Nonrecurring Basis
Investments in U.S. Treasury bills			471,962
Recurring | Level 2
Financial Assets and Liabilities Measured at Fair Value on a Recurring and Nonrecurring Basis
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)	260,747		183,804
Total assets	260,747		183,804
Mandatorily redeemable instruments (included in other liabilities)	0		0
Recurring | Level 2 | Investments in U.S. Treasury bills
Financial Assets and Liabilities Measured at Fair Value on a Recurring and Nonrecurring Basis
Investments in U.S. Treasury bills			0
Recurring | Level 3
Financial Assets and Liabilities Measured at Fair Value on a Recurring and Nonrecurring Basis
Deferred compensation plan assets (included in restricted cash and other assets)	45,687		38,916
Loans receivable (included in investments in partially owned entities and in other assets)	57,841		54,397
Interest rate swaps and caps (included in other assets)	0		0
Total assets	103,528		93,313
Mandatorily redeemable instruments (included in other liabilities)	0		0
Recurring | Level 3 | Investments in U.S. Treasury bills
Financial Assets and Liabilities Measured at Fair Value on a Recurring and Nonrecurring Basis
Investments in U.S. Treasury bills			0
Restricted Cash | Recurring
Financial Assets and Liabilities Measured at Fair Value on a Recurring and Nonrecurring Basis
Deferred compensation plan assets (included in restricted cash and other assets)	27,094		7,763
Other Assets | Recurring
Financial Assets and Liabilities Measured at Fair Value on a Recurring and Nonrecurring Basis
Deferred compensation plan assets (included in restricted cash and other assets)	73,392		88,559
Loans receivable (included in investments in partially owned entities and in other assets)	4,745		4,306
Investments in Partially Owned Properties | Recurring
Financial Assets and Liabilities Measured at Fair Value on a Recurring and Nonrecurring Basis
Loans receivable (included in investments in partially owned entities and in other assets)	$ 53,096		$ 50,091