Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 558,877	$ 513,503	$ 348,795
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	314,096	265,101	190,390
Amortization and write-off of financing costs on extinguished debt	12,311	13,155	28,871
Amortization of debt discount			9,477
Non-amortizable intangible asset impairment			98,129
Write-down of impaired other assets		8,615
Gain on sale of loans, servicing rights and other assets	(140,828)	(95,636)	(93,613)
Net realized and unrealized losses (gains) from investments	3,809	(11,237)	(13,523)
Gain on disposition of real estate held for investment	(10,771)	(57,659)	(13,552)
Equity income from unconsolidated subsidiaries	(162,849)	(101,714)	(64,422)
Provision for doubtful accounts	10,211	8,165	9,579
Deferred income taxes	(14,935)	(28,469)	(11,591)
Compensation expense related to equity awards	74,709	59,757	48,429
Incremental tax benefit from stock options exercised	(2,277)	(1,218)	(9,891)
Distribution of earnings from unconsolidated subsidiaries	36,630	27,903	33,302
Tenant concessions received	7,861	18,343	14,627
Purchase of trading securities	(85,707)	(71,021)	(137,311)
Proceeds from sale of trading securities	78,798	74,237	191,121
Proceeds from securities sold, not yet purchased	16,014	2,271	52,472
Securities purchased to cover short sales	(13,147)	(453)	(110,588)
Increase in receivables	(231,979)	(307,979)	(76,946)
Increase in prepaid expenses and other assets	(84,997)	(47,015)	(33,355)
(Increase) decrease in real estate held for sale and under development	(16,003)	47,276	168,133
Increase in accounts payable and accrued expenses	177,567	31,526	40,200
Increase in compensation and employee benefits payable and accrued bonus and profit sharing	115,805	344,987	102,439
Decrease (increase) in income taxes receivable/payable	43,085	(43,194)	3,077
(Decrease) increase in other liabilities	(15,543)	589	(6,808)
Other operating activities, net	(21,038)	(17,707)	(18,067)
Net cash provided by operating activities	651,897	661,780	745,108
CASH FLOWS FROM INVESTING ACTIVITIES:
Capital expenditures	(139,464)	(171,242)	(156,358)
Acquisition of businesses, including net assets acquired, intangibles and goodwill, net of cash acquired	(161,106)	(147,057)	(504,147)
Contributions to unconsolidated subsidiaries	(71,208)	(59,177)	(49,594)
Distributions from unconsolidated subsidiaries	187,577	104,267	82,230
Net proceeds from disposition of real estate held for investment	3,584	77,278	113,241
Additions to real estate held for investment	(2,053)	(10,961)	(2,559)
Proceeds from the sale of servicing rights and other assets	30,432	25,541	32,016
(Increase) decrease in restricted cash	(49,012)	30,889	8,469
Purchase of available for sale securities	(40,287)	(89,885)	(65,111)
Proceeds from the sale of available for sale securities	42,572	88,214	69,688
Other investing activities, net	1,669	577	7,131
Net cash used in investing activities	(1,618,959)	(151,556)	(464,994)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from senior secured term loans	900,000		715,000
Repayment of senior secured term loans	(657,488)	(39,650)	(1,639,017)
Proceeds from revolving credit facility	2,643,500	1,873,568	610,562
Repayment of revolving credit facility	(2,648,012)	(1,999,422)	(542,150)
Proceeds from issuance of senior notes	595,440	426,875	800,000
Repayment of 6.625% senior notes		(350,000)
Repayment of 11.625% senior subordinated notes			(450,000)
Proceeds from notes payable on real estate held for investment		5,022	2,762
Repayment of notes payable on real estate held for investment	(1,576)	(27,563)	(74,544)
Proceeds from notes payable on real estate held for sale and under development	20,879	8,274	9,526
Repayment of notes payable on real estate held for sale and under development	(1,186)	(80,218)	(136,528)
Shares repurchased for payment of taxes on equity awards	(24,523)	(16,685)	(16,628)
Proceeds from exercise of stock options	7,525	6,203	5,780
Incremental tax benefit from stock options exercised	2,277	1,218	9,891
Non-controlling interests contributions	5,909	2,938	1,092
Non-controlling interests distributions	(16,582)	(33,971)	(128,168)
Payment of financing costs	(30,664)	(5,947)	(29,322)
Other financing activities, net	(5,951)	(2,711)	(4,537)
Net cash (used in) provided by financing activities	789,548	(232,069)	(866,281)
Effect of currency exchange rate changes on cash and cash equivalents	(22,967)	(29,183)	(11,218)
NET (DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	(200,481)	248,972	(597,385)
CASH AND CASH EQUIVALENTS, AT BEGINNING OF PERIOD	740,884	491,912	1,089,297
CASH AND CASH EQUIVALENTS, AT END OF PERIOD	540,403	740,884	491,912
Cash paid during the period for:
Interest	88,078	118,749	117,150
Income tax payments, net	285,730	331,257	203,402
5.25% Senior Notes [Member]
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of senior notes		426,875
6.625% senior notes [Member]
CASH FLOWS FROM FINANCING ACTIVITIES:
Repayment of 6.625% senior notes		$ (350,000)
5.00% Senior Notes [Member]
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of senior notes			800,000
11.625% senior subordinated notes [Member]
CASH FLOWS FROM FINANCING ACTIVITIES:
Repayment of 11.625% senior subordinated notes			$ (450,000)
Global Workplace Solutions (GWS) [Member]
CASH FLOWS FROM INVESTING ACTIVITIES:
Acquisition of businesses, including net assets acquired, intangibles and goodwill, net of cash acquired	$ (1,421,663)