Corporate Indebtedness (Details 3) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014
Scheduled Amortization and Principal Repayments
2015	$ 259,360
2016	648,117
2017	1,311,400
2018	715,462
2019	932,450
Thereafter	4,602,185
Total amortization of debt and principal repayments	8,468,974
Mortgages and other loans payable
Scheduled Amortization
2015	39,353	[1]
2016	54,344	[1]
2017	61,063
2018	64,462
2019	71,133
Thereafter	203,098
Total amortization of debt	493,453	[1]
Principal Repayments
2015	220,000
2016	338,465	[1]
2017	895,329
2018	16,000
2019	28,317
Thereafter	3,849,087
Total principal repayments	5,347,198	[1]
Term loan
Scheduled Amortization and Principal Repayments
2015	0
2016	0
2017	0
2018	0
2019	833,000
Thereafter	0
Total amortization of debt and principal repayments	833,000
2011 Revolving Credit Facility
Scheduled Amortization and Principal Repayments
2015	0
2016	0
2017	0
2018	385,000
2019	0
Thereafter	0
Total amortization of debt and principal repayments	385,000
Term Loans and Trust Preferred Securities
Scheduled Amortization and Principal Repayments
2015	0
2016	0
2017	0
2018	0
2019	0
Thereafter	100,000
Total amortization of debt and principal repayments	100,000
Senior Unsecured Notes
Scheduled Amortization and Principal Repayments
2015	7
2016	255,308
2017	355,008
2018	250,000
2019	0
Thereafter	450,000
Total amortization of debt and principal repayments	1,310,323
Joint venture
Principal Repayments
2015	44,700
2016	640,176
2017	572,003
2018	28
2019	94,890
Thereafter	266,191
Total principal repayments	$ 1,617,988

[1] Scheduled amortization and principal repayments include the mortgage at 180 Maiden Lane, which is included in liabilities related to assets held for sale. In January 2015, the property was sold and the debt was repaid.