Consolidated Statements of Cash Flows (USD $)	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010
Net cash flows from operating activities:
Net income (loss)	$ 197,244,000	$ (44,773,000)
Adjustments to reconcile net income (loss) to net cash provided by (used for) operations:
Deferred income tax provision (benefit)	121,608,000	(5,347,000)
Depreciation and amortization of property, equipment and leasehold improvements	33,146,000	40,851,000
Other amortization	13,962,000	11,661,000
Share-based compensation	14,460,000	2,711,000
Excess tax benefit from exercise of stock options	(237,000)	(9,000)
Provision for doubtful accounts	254,000	2,907,000
Net securities gains	(531,940,000)	(170,480,000)
Losses related to associated companies	270,112,000	175,425,000
Distributions from associated companies	32,441,000	15,916,000
Net gains related to real estate, property and equipment, and other assets	(89,351,000)	(10,435,000)
Income related to Fortescue's Pilbara project, net of proceeds received	(28,798,000)	(68,258,000)
Loss on buyback of debt	6,352,000
Gain on disposal of discontinued operations	(1,423,000)
Change in estimated litigation reserve	(2,241,000)
Net change in:
Restricted cash	1,368,000	(21,851,000)
Trade, notes and other receivables	(7,810,000)	(10,935,000)
Prepaids and other assets	1,593,000	(1,134,000)
Trade payables and expense accruals	(22,266,000)	9,928,000
Other liabilities	(3,622,000)	2,898,000
Deferred revenue	(482,000)	8,521,000
Income taxes payable	(1,933,000)	5,275,000
Other	(513,000)	(513,000)
Net cash provided by (used for) operating activities	1,924,000	(57,642,000)
Net cash flows from investing activities:
Acquisition of property, equipment and leasehold improvements	(21,264,000)	(12,583,000)
Acquisitions of and capital expenditures for real estate investments	(6,190,000)	(6,323,000)
Proceeds from disposals of real estate, property and equipment, and other assets	23,326,000	4,473,000
Net change in restricted cash	5,426,000	(40,000)
Settlement of lawsuit		1,942,000
Proceeds from sales of discontinued operations	1,702,000
Acquisitions, net of cash acquired	(86,306,000)	(191,000)
Advances on notes and other receivables	(3,171,000)	(4,231,000)
Collections on notes, loans and other receivables	10,112,000	11,130,000
Investments in associated companies	(126,073,000)	(11,137,000)
Capital distributions and loan repayment from associated companies	271,076,000	29,319,000
Purchases of investments (other than short-term)	(1,232,513,000)	(542,792,000)
Proceeds from maturities of investments	268,806,000	106,799,000
Proceeds from sales of investments	869,087,000	541,450,000
Other	3,498,000	258,000
Net cash provided by (used for) investing activities	(22,484,000)	118,074,000
Net cash flows from financing activities:
Issuance of debt, net of issuance costs	258,984,000	39,011,000
Reduction of debt	(143,836,000)	(4,324,000)
Issuance of common shares	6,853,000	619,000
Excess tax benefit from exercise of stock options	237,000	9,000
Other	(3,926,000)	(1,638,000)
Net cash provided by financing activities	118,312,000	33,677,000
Net increase in cash and cash equivalents	97,752,000	94,109,000
Cash and cash equivalents at January 1, including cash classified as current assets of discontinued operations	441,340,000	154,128,000
Cash and cash equivalents at June 30, including cash classified as current assets of discontinued operations	539,092,000	248,237,000
Supplemental disclosures of cash flow information:
Interest	58,235,000	61,570,000
Income tax payments, net	$ 13,042,000	$ 2,838,000