Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Cash flows from operating activities:
Net income	$ 67,756	$ 57,931
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	154,270	121,191
Non-cash compensation expense	10,380	25,783
Impairment loss	0	8,306
Income from unconsolidated joint ventures	(2,816)	(8,721)
Distributions of net cash flow from operations of unconsolidated joint ventures	1,431	12,921
Gains from investments in securities	(286)	(735)
Non-cash portion of interest expense	(7,676)	10,561
Settlement of accreted debt discount on repurchases of unsecured exchangeable senior notes	(92,979)	0
Gain on forgiveness of debt from discontinued operations	0	(20,182)
Impairment loss from discontinued operations	0	3,241
Change in assets and liabilities:
Cash held in escrows	2,961	(297)
Tenant and other receivables, net	21,652	10,690
Accrued rental income, net	(10,127)	(14,295)
Prepaid expenses and other assets	5,989	18,684
Accounts payable and accrued expenses	1,288	(1,172)
Accrued interest payable	11,128	30,158
Other liabilities	(22,197)	(7,703)
Tenant leasing costs	(16,565)	(8,932)
Total adjustments	56,453	179,498
Net cash provided by operating activities	124,209	237,429
Cash flows from investing activities:
Acquisitions of real estate	0	(289,816)
Construction in progress	(97,025)	(103,178)
Building and other capital improvements	(17,510)	(14,162)
Tenant improvements	(31,551)	(24,988)
Repayments of notes receivable, net	0	184
Capital contributions to unconsolidated joint ventures	0	(113)
Capital distributions from unconsolidated joint ventures	113	0
Investments in securities, net	(1,099)	(918)
Net cash used in investing activities	(147,072)	(432,991)
Cash flows from financing activities:
Repayments of mortgage notes payable	(6,630)	(23,687)
Redemption/repurchase of unsecured exchangeable senior notes	(654,521)	0
Deferred financing costs	(18)	0
Net proceeds from preferred stock issuance	0	194,371
Net proceeds from equity transactions	(527)	(559)
Dividends and distributions	(496,330)	(110,940)
Contributions from noncontrolling interest in property partnerships	468	5,875
Distributions to noncontrolling interest in property partnerships	(5,143)	(2,100)
Net cash provided by (used in) financing activities	(1,162,701)	62,960
Net decrease in cash and cash equivalents	(1,185,564)	(132,602)
Cash and cash equivalents, beginning of period	2,365,137	1,041,978
Cash and cash equivalents, end of period	1,179,573	909,376
Supplemental disclosures:
Cash paid for interest	220,790	74,492
Interest capitalized	17,709	14,418
Non-cash investing and financing activities:
Additions to real estate included in accounts payable and accrued expenses	9,393	7,475
Mortgage note payable extinguished through foreclosure	0	25,000
Real estate transferred upon foreclosure	0	7,508
Land improvements contributed by noncontrolling interest in property partnership	0	4,546
Dividends and distributions declared but not paid	114,799	110,886
Conversions of noncontrolling interests to stockholders' equity	627	272
Issuance of restricted securities to employees and directors	$ 26,534	$ 25,901