Supplemental and Noncash Information (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Other Significant Noncash Transactions [Line Items]
Cash paid for interest, net of amounts capitalized	$ 223,793	$ 233,220	$ 265,430
Accrued dividends and distributions payable	50,523	43,689	41,717
Additions to real estate assets accrued but not yet paid	20,625	22,468	21,771
Reduction to preferred liquidation value of PJV units	10,000	0	0
Discount on issuance of 5.250% Senior Notes due 2023	(4,626)	0	0
Weighted average interest rate	4.88%	4.79%
Trade-in allowance - aircraft	2,800	0	0
Notes receivable from sale of land	7,430	0	0
Issuance of noncontrolling interests in Operating Partnership	0	14,000	0
Conversion of Operating Partnership units to common stock	0	59,738	729
Addition to real estate assets from conversion of note receivable	0	4,522	0
Increase in mortgage and other indebtedness	0	220,634	0
Additions to real estate assets from forgiveness of mortgage note receivable	0	0	2,235
Partnership Interest [Member] | Consolidation of Joint Venture [Member]
Other Significant Noncash Transactions [Line Items]
Increase in mortgage and other indebtedness	0	54,169	0
Decrease in investment in unconsolidated affiliates	0	(15,643)	0
Increase/decrease in real estate assets	0	111,407	0
Increase in intangible lease and other assets	0	18,426	0
Partnership Interest [Member] | Deconsolidation of Joint Venture [Member]
Other Significant Noncash Transactions [Line Items]
Increase/decrease in real estate assets	0	0	365,971
Decrease in intangible lease and other assets	0	0	26,798
Decrease in mortgage notes payable	0	0	(266,224)
Increase in investment in unconsolidated affiliates	0	0	(123,651)
Decrease in accounts payable and accrued liabilities	$ 0	$ 0	$ (4,395)
Senior Unsecured Notes [Member]
Other Significant Noncash Transactions [Line Items]
Weighted average interest rate	5.25%