Schedule III-Real Estate And Accumulated Depreciation (Details) (USD $)	Dec. 31, 2012
Real Estate And Accumulated Depreciation
Encumbrances	$ 4,448,774,000
Initial Cost
Land	2,626,639,000
Building & Improvements	7,938,087,000
Cost Capitalized Subsequent To Acquisition
Land	259,460,000
Building & Improvements	838,767,000
Gross Amount at Which Carried at Close of Period
Land	2,886,099,000
Building & Improvements	8,776,854,000
Total	11,662,953,000
Accumulated Depreciation	1,393,323,000
673 First Ave
Initial Cost
Building & Improvements	35,727,000
Cost Capitalized Subsequent To Acquisition
Building & Improvements	12,008,000
Gross Amount at Which Carried at Close of Period
Building & Improvements	47,735,000
Total	47,735,000
Accumulated Depreciation	18,538,000
420 Lexington Ave
Real Estate And Accumulated Depreciation
Encumbrances	184,992,000
Initial Cost
Building & Improvements	107,832,000
Cost Capitalized Subsequent To Acquisition
Building & Improvements	150,505,000
Gross Amount at Which Carried at Close of Period
Building & Improvements	258,337,000
Total	258,337,000
Accumulated Depreciation	78,299,000
711 Third Avenue
Real Estate And Accumulated Depreciation
Encumbrances	120,000,000
Initial Cost
Land	19,844,000
Building & Improvements	42,499,000
Cost Capitalized Subsequent To Acquisition
Building & Improvements	32,412,000
Gross Amount at Which Carried at Close of Period
Land	19,844,000
Building & Improvements	74,911,000
Total	94,755,000
Accumulated Depreciation	26,054,000
555 W. 57th Street
Initial Cost
Land	18,846,000
Building & Improvements	78,704,000
Cost Capitalized Subsequent To Acquisition
Building & Improvements	37,612,000
Gross Amount at Which Carried at Close of Period
Land	18,846,000
Building & Improvements	116,316,000
Total	135,162,000
Accumulated Depreciation	40,143,000
317 Madison Ave
Initial Cost
Land	21,205,000
Building & Improvements	85,559,000
Cost Capitalized Subsequent To Acquisition
Building & Improvements	28,469,000
Gross Amount at Which Carried at Close of Period
Land	21,205,000
Building & Improvements	114,028,000
Total	135,233,000
Accumulated Depreciation	46,077,000
220 East 42nd Street
Real Estate And Accumulated Depreciation
Encumbrances	185,906,000
Initial Cost
Land	50,373,000
Building & Improvements	203,727,000
Cost Capitalized Subsequent To Acquisition
Land	635,000
Building & Improvements	42,141,000
Gross Amount at Which Carried at Close of Period
Land	51,008,000
Building & Improvements	245,868,000
Total	296,876,000
Accumulated Depreciation	64,001,000
461 Fifth Avenue
Initial Cost
Building & Improvements	62,695,000
Cost Capitalized Subsequent To Acquisition
Building & Improvements	6,738,000
Gross Amount at Which Carried at Close of Period
Building & Improvements	69,433,000
Total	69,433,000
Accumulated Depreciation	17,444,000
750 Third Avenue
Initial Cost
Land	51,093,000
Building & Improvements	205,972,000
Cost Capitalized Subsequent To Acquisition
Building & Improvements	30,120,000
Gross Amount at Which Carried at Close of Period
Land	51,093,000
Building & Improvements	236,092,000
Total	287,185,000
Accumulated Depreciation	54,689,000
625 Madison Ave
Real Estate And Accumulated Depreciation
Encumbrances	125,603,000
Initial Cost
Building & Improvements	246,673,000
Cost Capitalized Subsequent To Acquisition
Building & Improvements	28,502,000
Gross Amount at Which Carried at Close of Period
Building & Improvements	275,175,000
Total	275,175,000
Accumulated Depreciation	60,598,000
485 Lexington Avenue
Real Estate And Accumulated Depreciation
Encumbrances	450,000,000
Initial Cost
Land	77,517,000
Building & Improvements	326,825,000
Cost Capitalized Subsequent To Acquisition
Land	765,000
Building & Improvements	86,025,000
Gross Amount at Which Carried at Close of Period
Land	78,282,000
Building & Improvements	412,850,000
Total	491,132,000
Accumulated Depreciation	98,492,000
609 Fifth Avenue
Initial Cost
Land	36,677,000
Building & Improvements	145,954,000
Cost Capitalized Subsequent To Acquisition
Building & Improvements	4,640,000
Gross Amount at Which Carried at Close of Period
Land	36,677,000
Building & Improvements	150,594,000
Total	187,271,000
Accumulated Depreciation	24,420,000
120 West 45th Street
Real Estate And Accumulated Depreciation
Encumbrances	170,000,000
Initial Cost
Land	60,766,000
Building & Improvements	250,922,000
Cost Capitalized Subsequent To Acquisition
Building & Improvements	12,635,000
Gross Amount at Which Carried at Close of Period
Land	60,766,000
Building & Improvements	263,557,000
Total	324,323,000
Accumulated Depreciation	42,272,000
810 Seventh Avenue
Initial Cost
Land	114,077,000
Building & Improvements	476,386,000
Cost Capitalized Subsequent To Acquisition
Building & Improvements	39,315,000
Gross Amount at Which Carried at Close of Period
Land	114,077,000
Building & Improvements	515,701,000
Total	629,778,000
Accumulated Depreciation	83,226,000
919 Third Avenue
Real Estate And Accumulated Depreciation
Encumbrances	500,000,000
Initial Cost
Land	223,529,000
Building & Improvements	1,033,198,000
Cost Capitalized Subsequent To Acquisition
Land	35,410,000
Building & Improvements	8,084,000
Gross Amount at Which Carried at Close of Period
Land	258,939,000
Building & Improvements	1,041,282,000
Total	1,300,221,000
Accumulated Depreciation	160,004,000
1185 Avenue of the Americas
Initial Cost
Building & Improvements	728,213,000
Cost Capitalized Subsequent To Acquisition
Building & Improvements	30,143,000
Gross Amount at Which Carried at Close of Period
Building & Improvements	758,356,000
Total	758,356,000
Accumulated Depreciation	129,505,000
1350 Avenue of the Americas
Initial Cost
Land	91,038,000
Building & Improvements	380,744,000
Cost Capitalized Subsequent To Acquisition
Building & Improvements	22,694,000
Gross Amount at Which Carried at Close of Period
Land	91,038,000
Building & Improvements	403,438,000
Total	494,476,000
Accumulated Depreciation	66,036,000
1100 King Street - 1-7 International Drive
Initial Cost
Land	49,392,000
Building & Improvements	104,376,000
Cost Capitalized Subsequent To Acquisition
Land	2,473,000
Building & Improvements	8,795,000
Gross Amount at Which Carried at Close of Period
Land	51,865,000
Building & Improvements	113,171,000
Total	165,036,000
Accumulated Depreciation	21,597,000
520 White Plains Road
Initial Cost
Land	6,324,000
Building & Improvements	26,096,000
Cost Capitalized Subsequent To Acquisition
Building & Improvements	2,593,000
Gross Amount at Which Carried at Close of Period
Land	6,324,000
Building & Improvements	28,689,000
Total	35,013,000
Accumulated Depreciation	5,545,000
115-117 Stevens Avenue
Initial Cost
Land	5,933,000
Building & Improvements	23,826,000
Cost Capitalized Subsequent To Acquisition
Building & Improvements	5,177,000
Gross Amount at Which Carried at Close of Period
Land	5,933,000
Building & Improvements	29,003,000
Total	34,936,000
Accumulated Depreciation	5,703,000
100 Summit Lake Drive
Initial Cost
Land	10,526,000
Building & Improvements	43,109,000
Cost Capitalized Subsequent To Acquisition
Building & Improvements	6,762,000
Gross Amount at Which Carried at Close of Period
Land	10,526,000
Building & Improvements	49,871,000
Total	60,397,000
Accumulated Depreciation	8,464,000
200 Summit Lake Drive
Initial Cost
Land	11,183,000
Building & Improvements	47,906,000
Cost Capitalized Subsequent To Acquisition
Building & Improvements	3,263,000
Gross Amount at Which Carried at Close of Period
Land	11,183,000
Building & Improvements	51,169,000
Total	62,352,000
Accumulated Depreciation	8,847,000
500 Summit Lake Drive
Initial Cost
Land	9,777,000
Building & Improvements	39,048,000
Cost Capitalized Subsequent To Acquisition
Building & Improvements	4,183,000
Gross Amount at Which Carried at Close of Period
Land	9,777,000
Building & Improvements	43,231,000
Total	53,008,000
Accumulated Depreciation	6,701,000
140 Grand Street
Initial Cost
Land	6,865,000
Building & Improvements	28,264,000
Cost Capitalized Subsequent To Acquisition
Building & Improvements	3,557,000
Gross Amount at Which Carried at Close of Period
Land	6,865,000
Building & Improvements	31,821,000
Total	38,686,000
Accumulated Depreciation	5,503,000
360 Hamilton Avenue
Initial Cost
Land	29,497,000
Building & Improvements	118,250,000
Cost Capitalized Subsequent To Acquisition
Building & Improvements	10,549,000
Gross Amount at Which Carried at Close of Period
Land	29,497,000
Building & Improvements	128,799,000
Total	158,296,000
Accumulated Depreciation	21,318,000
1-6 Landmark Square
Real Estate And Accumulated Depreciation
Encumbrances	84,486,000
Initial Cost
Land	50,947,000
Building & Improvements	195,167,000
Cost Capitalized Subsequent To Acquisition
Building & Improvements	20,533,000
Gross Amount at Which Carried at Close of Period
Land	50,947,000
Building & Improvements	215,700,000
Total	266,647,000
Accumulated Depreciation	34,333,000
7 Landmark Square
Initial Cost
Land	2,088,000
Building & Improvements	7,748,000
Cost Capitalized Subsequent To Acquisition
Land	(367,000)
Building & Improvements	(153,000)
Gross Amount at Which Carried at Close of Period
Land	1,721,000
Building & Improvements	7,595,000
Total	9,316,000
Accumulated Depreciation	209,000
300 Main Street
Real Estate And Accumulated Depreciation
Encumbrances	11,500,000
Initial Cost
Land	3,025,000
Building & Improvements	12,889,000
Cost Capitalized Subsequent To Acquisition
Building & Improvements	1,383,000
Gross Amount at Which Carried at Close of Period
Land	3,025,000
Building & Improvements	14,272,000
Total	17,297,000
Accumulated Depreciation	2,472,000
680 Washington Boulevard
Initial Cost
Land	11,696,000
Building & Improvements	45,364,000
Cost Capitalized Subsequent To Acquisition
Building & Improvements	4,031,000
Gross Amount at Which Carried at Close of Period
Land	11,696,000
Building & Improvements	49,395,000
Total	61,091,000
Accumulated Depreciation	8,040,000
Interest in property (as a percent)	51.00%
750 Washington Boulevard
Initial Cost
Land	16,916,000
Building & Improvements	68,849,000
Cost Capitalized Subsequent To Acquisition
Building & Improvements	3,995,000
Gross Amount at Which Carried at Close of Period
Land	16,916,000
Building & Improvements	72,844,000
Total	89,760,000
Accumulated Depreciation	11,962,000
Interest in property (as a percent)	51.00%
1010 Washington Boulevard
Initial Cost
Land	7,747,000
Building & Improvements	30,423,000
Cost Capitalized Subsequent To Acquisition
Building & Improvements	3,354,000
Gross Amount at Which Carried at Close of Period
Land	7,747,000
Building & Improvements	33,777,000
Total	41,524,000
Accumulated Depreciation	5,447,000
500 West Putnam Avenue
Real Estate And Accumulated Depreciation
Encumbrances	24,060,000
Initial Cost
Land	11,210,000
Building & Improvements	44,782,000
Cost Capitalized Subsequent To Acquisition
Building & Improvements	4,481,000
Gross Amount at Which Carried at Close of Period
Land	11,210,000
Building & Improvements	49,263,000
Total	60,473,000
Accumulated Depreciation	7,430,000
150 Grand Street
Initial Cost
Land	1,371,000
Building & Improvements	5,446,000
Cost Capitalized Subsequent To Acquisition
Building & Improvements	10,119,000
Gross Amount at Which Carried at Close of Period
Land	1,371,000
Building & Improvements	15,565,000
Total	16,936,000
Accumulated Depreciation	563,000
400 Summit Lake Drive
Initial Cost
Land	38,889,000
Cost Capitalized Subsequent To Acquisition
Land	285,000
Building & Improvements	1,000
Gross Amount at Which Carried at Close of Period
Land	39,174,000
Building & Improvements	1,000
Total	39,175,000
331 Madison Avenue
Initial Cost
Land	14,763,000
Building & Improvements	65,241,000
Cost Capitalized Subsequent To Acquisition
Land	(2,630,000)
Building & Improvements	(12,115,000)
Gross Amount at Which Carried at Close of Period
Land	12,133,000
Building & Improvements	53,126,000
Total	65,259,000
Accumulated Depreciation	8,556,000
333 West 34th Street
Initial Cost
Land	36,711,000
Building & Improvements	146,880,000
Cost Capitalized Subsequent To Acquisition
Building & Improvements	22,507,000
Gross Amount at Which Carried at Close of Period
Land	36,711,000
Building & Improvements	169,387,000
Total	206,098,000
Accumulated Depreciation	24,308,000
1055 Washington Boulevard
Initial Cost
Land	13,516,000
Building & Improvements	53,228,000
Cost Capitalized Subsequent To Acquisition
Building & Improvements	2,524,000
Gross Amount at Which Carried at Close of Period
Land	13,516,000
Building & Improvements	55,752,000
Total	69,268,000
Accumulated Depreciation	9,008,000
1 Madison Avenue
Real Estate And Accumulated Depreciation
Encumbrances	607,678,000
Initial Cost
Land	172,641,000
Building & Improvements	654,394,000
Cost Capitalized Subsequent To Acquisition
Land	905,000
Building & Improvements	12,848,000
Gross Amount at Which Carried at Close of Period
Land	173,546,000
Building & Improvements	667,242,000
Total	840,788,000
Accumulated Depreciation	90,742,000
125 Chubb Way
Initial Cost
Land	5,884,000
Building & Improvements	25,958,000
Cost Capitalized Subsequent To Acquisition
Building & Improvements	23,169,000
Gross Amount at Which Carried at Close of Period
Land	5,884,000
Building & Improvements	49,127,000
Total	55,011,000
Accumulated Depreciation	1,669,000
100 Church Street
Real Estate And Accumulated Depreciation
Encumbrances	230,000,000
Initial Cost
Land	32,494,000
Building & Improvements	79,996,000
Cost Capitalized Subsequent To Acquisition
Land	2,500,000
Building & Improvements	56,673,000
Gross Amount at Which Carried at Close of Period
Land	34,994,000
Building & Improvements	136,669,000
Total	171,663,000
Accumulated Depreciation	14,445,000
125 Park Avenue
Real Estate And Accumulated Depreciation
Encumbrances	146,250,000
Initial Cost
Land	120,900,000
Building & Improvements	189,714,000
Cost Capitalized Subsequent To Acquisition
Building & Improvements	18,791,000
Gross Amount at Which Carried at Close of Period
Land	120,900,000
Building & Improvements	208,505,000
Total	329,405,000
Accumulated Depreciation	16,538,000
2 Herald Square
Real Estate And Accumulated Depreciation
Encumbrances	191,250,000
Initial Cost
Land	92,655,000
Cost Capitalized Subsequent To Acquisition
Land	100,633,000
Gross Amount at Which Carried at Close of Period
Land	193,288,000
Total	193,288,000
885 Third Avenue
Real Estate And Accumulated Depreciation
Encumbrances	267,650,000
Initial Cost
Land	131,766,000
Cost Capitalized Subsequent To Acquisition
Land	110,771,000
Gross Amount at Which Carried at Close of Period
Land	242,537,000
Total	242,537,000
Williamsburg
Initial Cost
Land	3,677,000
Building & Improvements	14,708,000
Cost Capitalized Subsequent To Acquisition
Land	2,523,000
Building & Improvements	(4,550,000)
Gross Amount at Which Carried at Close of Period
Land	6,200,000
Building & Improvements	10,158,000
Total	16,358,000
Accumulated Depreciation	560,000
1515 Broadway
Real Estate And Accumulated Depreciation
Encumbrances	769,813,000
Initial Cost
Land	462,700,000
Building & Improvements	707,938,000
Cost Capitalized Subsequent To Acquisition
Land	1,145,000
Building & Improvements	19,683,000
Gross Amount at Which Carried at Close of Period
Land	463,845,000
Building & Improvements	727,621,000
Total	1,191,466,000
Accumulated Depreciation	38,921,000
110 East 42nd Street
Initial Cost
Land	34,000,000
Building & Improvements	46,411,000
Cost Capitalized Subsequent To Acquisition
Building & Improvements	4,214,000
Gross Amount at Which Carried at Close of Period
Land	34,000,000
Building & Improvements	50,625,000
Total	84,625,000
Accumulated Depreciation	3,424,000
180 Maiden Lane
Real Estate And Accumulated Depreciation
Encumbrances	271,215,000
Initial Cost
Land	191,523,000
Building & Improvements	233,230,000
Cost Capitalized Subsequent To Acquisition
Building & Improvements	(683,000)
Gross Amount at Which Carried at Close of Period
Land	191,523,000
Building & Improvements	232,547,000
Total	424,070,000
Accumulated Depreciation	9,925,000
Interest in property (as a percent)	49.90%
51 East 42nd Street
Initial Cost
Land	44,095,000
Building & Improvements	33,470,000
Cost Capitalized Subsequent To Acquisition
Land	5,000
Building & Improvements	2,081,000
Gross Amount at Which Carried at Close of Period
Land	44,100,000
Building & Improvements	35,551,000
Total	79,651,000
Accumulated Depreciation	1,321,000
400 East 57th Street
Real Estate And Accumulated Depreciation
Encumbrances	70,000,000
Initial Cost
Land	39,780,000
Building & Improvements	69,895,000
Cost Capitalized Subsequent To Acquisition
Building & Improvements	3,181,000
Gross Amount at Which Carried at Close of Period
Land	39,780,000
Building & Improvements	73,076,000
Total	112,856,000
Accumulated Depreciation	1,667,000
Interest in property (as a percent)	80.00%
400 East 58th Street
Real Estate And Accumulated Depreciation
Encumbrances	30,000,000
Initial Cost
Land	17,549,000
Building & Improvements	30,916,000
Cost Capitalized Subsequent To Acquisition
Building & Improvements	1,106,000
Gross Amount at Which Carried at Close of Period
Land	17,549,000
Building & Improvements	32,022,000
Total	49,571,000
Accumulated Depreciation	723,000
Interest in property (as a percent)	80.00%
752 Madison Avenue
Initial Cost
Building & Improvements	7,131,000
Gross Amount at Which Carried at Close of Period
Building & Improvements	7,131,000
Total	7,131,000
Accumulated Depreciation	372,000
Interest in property (as a percent)	80.00%
762 Madison Avenue
Real Estate And Accumulated Depreciation
Encumbrances	8,371,000
Initial Cost
Land	6,153,000
Building & Improvements	10,461,000
Cost Capitalized Subsequent To Acquisition
Building & Improvements	11,000
Gross Amount at Which Carried at Close of Period
Land	6,153,000
Building & Improvements	10,472,000
Total	16,625,000
Accumulated Depreciation	251,000
Interest in property (as a percent)	80.00%
19-21 East 65th Street
Initial Cost
Building & Improvements	7,389,000
Cost Capitalized Subsequent To Acquisition
Building & Improvements	132,000
Gross Amount at Which Carried at Close of Period
Building & Improvements	7,521,000
Total	7,521,000
Accumulated Depreciation	171,000
Interest in property (as a percent)	80.00%
304 Park Avenue
Initial Cost
Land	54,189,000
Building & Improvements	75,619,000
Cost Capitalized Subsequent To Acquisition
Land	300,000
Building & Improvements	1,109,000
Gross Amount at Which Carried at Close of Period
Land	54,489,000
Building & Improvements	76,728,000
Total	131,217,000
Accumulated Depreciation	1,715,000
635 Sixth Avenue
Initial Cost
Land	24,179,000
Building & Improvements	37,158,000
Cost Capitalized Subsequent To Acquisition
Land	164,000
Building & Improvements	803,000
Gross Amount at Which Carried at Close of Period
Land	24,343,000
Building & Improvements	37,961,000
Total	62,304,000
Accumulated Depreciation	234,000
641 Sixth Avenue
Initial Cost
Land	45,668,000
Building & Improvements	67,316,000
Cost Capitalized Subsequent To Acquisition
Land	308,000
Building & Improvements	430,000
Gross Amount at Which Carried at Close of Period
Land	45,976,000
Building & Improvements	67,746,000
Total	113,722,000
Accumulated Depreciation	629,000
1080 Amsterdam
Initial Cost
Building & Improvements	29,126,000
Gross Amount at Which Carried at Close of Period
Building & Improvements	29,126,000
Total	29,126,000
Interest in property (as a percent)	87.50%
131-137 Spring Street
Initial Cost
Land	36,915,000
Building & Improvements	86,135,000
Gross Amount at Which Carried at Close of Period
Land	36,915,000
Building & Improvements	86,135,000
Total	123,050,000
985-987 Third Avenue
Initial Cost
Land	5,400,000
Building & Improvements	12,600,000
Gross Amount at Which Carried at Close of Period
Land	5,400,000
Building & Improvements	12,600,000
Total	18,000,000
Other
Initial Cost
Land	1,130,000
Cost Capitalized Subsequent To Acquisition
Land	3,635,000
Building & Improvements	22,187,000
Gross Amount at Which Carried at Close of Period
Land	4,765,000
Building & Improvements	22,187,000
Total	26,952,000
Accumulated Depreciation	$ 4,212,000