Segment Information (Summary of NOI by Segment) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Information
Total revenues	$ 363,962	$ 465,961	$ 1,151,520	$ 1,463,732
Operating expenses	(195,645)	(226,359)	(600,077)	(694,006)
NOI - consolidated	168,317	239,602	551,443	769,726
Deduct: NOI attributable to noncontrolling interests in consolidated subsidiaries	(25,959)	(18,096)	(56,900)	(51,915)
Add: NOI from partially owned entities	78,175	86,024	229,543	236,400
NOI at share	220,533	307,530	724,086	954,211
Non-cash adjustments for straight-line rents, amortization of acquired below-market leases, net, and other	10,981	(4,037)	48,247	530
NOI at share - cash basis	231,514	303,493	772,333	954,741
New York
Segment Information
Total revenues	293,145	380,568	919,388	1,200,234
Operating expenses	(161,386)	(188,159)	(484,624)	(574,073)
NOI - consolidated	131,759	192,409	434,764	626,161
Deduct: NOI attributable to noncontrolling interests in consolidated subsidiaries	(17,776)	(9,574)	(34,713)	(31,011)
Add: NOI from partially owned entities	75,837	82,649	221,296	211,394
NOI at share	189,820	265,484	621,347	806,544
Non-cash adjustments for straight-line rents, amortization of acquired below-market leases, net, and other	6,261	(5,560)	40,310	(3,741)
NOI at share - cash basis	196,081	259,924	661,657	802,803
Other
Segment Information
Total revenues	70,817	85,393	232,132	263,498
Operating expenses	(34,259)	(38,200)	(115,453)	(119,933)
NOI - consolidated	36,558	47,193	116,679	143,565
Deduct: NOI attributable to noncontrolling interests in consolidated subsidiaries	(8,183)	(8,522)	(22,187)	(20,904)
Add: NOI from partially owned entities	2,338	3,375	8,247	25,006
NOI at share	30,713	42,046	102,739	147,667
Non-cash adjustments for straight-line rents, amortization of acquired below-market leases, net, and other	4,720	1,523	7,937	4,271
NOI at share - cash basis	$ 35,433	$ 43,569	$ 110,676	$ 151,938