Income Taxes (Details) (USD $)	3 Months Ended	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Income Taxes [Abstract]
New York City unincorporated business tax rate (in hundredths)		4.00%	4.00%	4.00%
Earnings before income taxes:
United States		$ (120,159,000)	$ 382,463,000	$ 539,002,000
Foreign		(88,310,000)	83,159,000	85,483,000
Total	540,200,000	(208,469,000)	465,622,000	624,485,000
Income tax expense: [Abstract]
Partnership UBT		8,737,000	10,363,000	2,420,000
Corporate subsidiaries:
Federal		10,600,000	2,570,000	5,550,000
State and local		1,772,000	1,401,000	632,000
Foreign		11,411,000	25,144,000	32,001,000
Current tax expense		32,520,000	39,478,000	40,603,000
Deferred tax expense (benefit)		(29,422,000)	(955,000)	5,374,000
Income tax benefit expense	20,300,000	3,098,000	38,523,000	45,977,000
Income Tax Expense (Benefit), Continuing Operations, Income Tax Reconciliation [Abstract]
UBT statutory rate		(8,339,000)	18,625,000	24,979,000
Corporate subsidiaries' federal, state, local and foreign income taxes		2,998,000	25,544,000	32,585,000
Effect of ASC 740 adjustments, miscellaneous taxes, and other		2,560,000	1,445,000	(1,988,000)
Income not taxable resulting from use of UBT business apportionment factors and effect of deferred compensation charge		5,879,000	(7,091,000)	(9,599,000)
Income tax expense	20,300,000	3,098,000	38,523,000	45,977,000
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
UBT statutory rate (in hundredths)		4.00%	4.00%	4.00%
Corporate subsidiaries' federal, state, local and foreign income taxes (in hundredths)		(1.40%)	5.50%	5.20%
Effect of ASC 740 adjustments, miscellaneous taxes, and other (in hundredths)		(1.30%)	0.30%	(0.30%)
Income not taxable resulting from use of UBT business apportionment factors and effect of deferred compensation charge (in hundredths)		(2.80%)	(1.50%)	(1.50%)
Effective Income Tax Rate (in hundredths)	3.80%	(1.50%)	8.30%	7.40%
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance as of beginning of period		5,326,000	7,365,000	8,805,000
Additions for prior year tax positions		190,000	0	174,000
Reductions for prior year tax positions		0	0	0
Additions for current year tax positions		761,000	823,000	1,182,000
Reductions for current year tax positions		0	0	(52,000)
Reductions related to closed years/settlements with tax authorities		(2,249,000)	(2,862,000)	(2,744,000)
Balance as of end of period	4,028,000	4,028,000	5,326,000	7,365,000
Total amount of interest expense (credit) recorded in income tax expense		(200,000)	(100,000)	(100,000)
Accrued interest recorded on the consolidated statements of financial condition	500,000	500,000	700,000	800,000
Examination was settled resulting in a tax payment				100,000
Components of deferred tax assets and liabilities
Benefits from net operating loss carryforwards	5,138,000	5,138,000	0
Deferred compensation plans	35,716,000	35,716,000	15,431,000
Other, primarily accrued expenses deductible when paid	14,398,000	14,398,000	7,183,000
Deferred tax asset	55,252,000	55,252,000	22,614,000
Less valuation allowance	(5,138,000)	(5,138,000)	0
Deferred tax asset	50,114,000	50,114,000	22,614,000
Components of deferred tax assets and liabilities
Intangible assets	14,325,000	14,325,000	14,575,000
Translation adjustment	9,413,000	9,413,000	8,303,000
Other, primarily undistributed earnings of certain foreign subsidiaries	330,000	330,000	2,979,000
Deferred tax asset (liability)	24,068,000	24,068,000	25,857,000
Net deferred tax liability	26,046,000	26,046,000	(3,243,000)
Accumulated undistributed earnings	573,800,000	573,800,000
NOL foreign locations	31,100,000	31,100,000
Additional taxes provided due to existing income tax rate	20,100,000	20,100,000
Recognition of unrecognized tax benefits	1,300,000	1,300,000
Income tax expenses decreased		35,400,000	7,500,000
Income tax expenses decreased (in hundredths)		92.00%	16.20%
Effective tax rate in reporting period	3.80%	(1.50%)	8.30%	7.40%
Pre-tax loss	540,200,000	(208,469,000)	465,622,000	624,485,000
Income tax benefit expense	20,300,000	3,098,000	38,523,000	45,977,000
Estimated effective income tax rate (in hundredths)		7.10%
Deferred compensation charges	$ 587,131,000	$ 587,131,000	$ 0	$ 0