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