Organization and Basis of Presentation - Schedule of Commercial Office Properties (Details)	Sep. 30, 2022 ft² building
Real estate properties
Number of Buildings | building	52
Approximate Square Feet unaudited (sqft)	30,122,545
Weighted Average Occupancy unaudited (as a percent)	90.90%
Commercial properties
Real estate properties
Number of Buildings | building	51
Approximate Square Feet unaudited (sqft)	29,982,163
Weighted Average Occupancy unaudited (as a percent)	91.00%
Consolidated
Real estate properties
Number of Buildings | building	28
Approximate Square Feet unaudited (sqft)	13,075,927
Consolidated | Commercial properties
Real estate properties
Number of Buildings | building	27
Approximate Square Feet unaudited (sqft)	12,935,545
Unconsolidated
Real estate properties
Number of Buildings | building	24
Approximate Square Feet unaudited (sqft)	17,046,618
Unconsolidated | Commercial properties
Real estate properties
Number of Buildings | building	24
Approximate Square Feet unaudited (sqft)	17,046,618
Manhattan
Real estate properties
Number of Buildings | building	44
Approximate Square Feet unaudited (sqft)	29,119,363
Weighted Average Occupancy unaudited (as a percent)	91.40%
Manhattan | Office
Real estate properties
Number of Buildings | building	25
Approximate Square Feet unaudited (sqft)	23,961,519
Weighted Average Occupancy unaudited (as a percent)	91.40%
Manhattan | Retail
Real estate properties
Number of Buildings | building	11
Approximate Square Feet unaudited (sqft)	319,884
Weighted Average Occupancy unaudited (as a percent)	91.20%
Manhattan | Development/Redevelopment
Real estate properties
Number of Buildings | building	8
Approximate Square Feet unaudited (sqft)	4,837,960
Manhattan | Residential
Real estate properties
Number of Buildings | building	1
Approximate Square Feet unaudited (sqft)	140,382
Weighted Average Occupancy unaudited (as a percent)	85.60%
Manhattan | Consolidated
Real estate properties
Number of Buildings | building	20
Approximate Square Feet unaudited (sqft)	12,072,745
Manhattan | Consolidated | Office
Real estate properties
Number of Buildings | building	13
Approximate Square Feet unaudited (sqft)	9,963,138
Manhattan | Consolidated | Retail
Real estate properties
Number of Buildings | building	2
Approximate Square Feet unaudited (sqft)	17,888
Manhattan | Consolidated | Retail | 7 Dey / 185 Broadway
Real estate properties
Approximate Square Feet unaudited (sqft)	140,382
Manhattan | Consolidated | Development/Redevelopment
Real estate properties
Number of Buildings | building	5
Approximate Square Feet unaudited (sqft)	2,091,719
Manhattan | Consolidated | Residential
Real estate properties
Number of Buildings | building	1
Approximate Square Feet unaudited (sqft)	140,382
Manhattan | Consolidated | Residential | 7 Dey / 185 Broadway
Real estate properties
Approximate Square Feet unaudited (sqft)	50,206
Manhattan | Unconsolidated
Real estate properties
Number of Buildings | building	24
Approximate Square Feet unaudited (sqft)	17,046,618
Manhattan | Unconsolidated | Office
Real estate properties
Number of Buildings | building	12
Approximate Square Feet unaudited (sqft)	13,998,381
Manhattan | Unconsolidated | Retail
Real estate properties
Number of Buildings | building	9
Approximate Square Feet unaudited (sqft)	301,996
Manhattan | Unconsolidated | Development/Redevelopment
Real estate properties
Number of Buildings | building	3
Approximate Square Feet unaudited (sqft)	2,746,241
Manhattan | Unconsolidated | Residential
Real estate properties
Number of Buildings | building	0
Approximate Square Feet unaudited (sqft)	0
Suburban | Office
Real estate properties
Number of Buildings | building	7
Approximate Square Feet unaudited (sqft)	862,800
Weighted Average Occupancy unaudited (as a percent)	80.10%
Suburban | Consolidated | Office
Real estate properties
Number of Buildings | building	7
Approximate Square Feet unaudited (sqft)	862,800
Suburban | Unconsolidated | Office
Real estate properties
Number of Buildings | building	0
Approximate Square Feet unaudited (sqft)	0