Guarantor and Nonguarantor Financial Statements - Condensed Consolidating Balance Sheet (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents	$ 762,576	$ 540,403	$ 740,884	$ 491,912
Restricted cash	68,836	72,764
Receivables, net	2,605,602	2,471,740
Warehouse receivables	1,276,047	1,767,107
Income taxes receivable	45,626	59,331
Prepaid expenses	184,107	172,922
Other current assets	179,656	220,956
Total Current Assets	5,122,450	5,305,223
Property and equipment, net	560,756	529,823
Goodwill	2,981,392	3,085,997	2,333,821
Other intangible assets, net	1,411,039	1,450,469
Investments in unconsolidated subsidiaries	232,238	217,943
Deferred tax assets, net	105,324	135,252
Other assets, net	366,388	293,236
Total Assets	10,779,587	11,017,943
Accounts payable and accrued expenses	1,446,438	1,484,119
Compensation and employee benefits payable	772,922	705,070
Accrued bonus and profit sharing	890,321	866,894
Income taxes payable	58,351	82,194
Warehouse lines of credit (which fund loans that U.S. Government Sponsored Entities have committed to purchase)	1,254,653	1,750,781
Other	16	16
Total short-term borrowings	1,254,669	1,750,797
Current maturities of long-term debt	11	34,428
Other current liabilities	102,717	70,655
Total Current Liabilities	4,525,429	4,994,157
Long-term debt, net	2,548,126	2,645,111
Total long-term debt, net	2,548,126	2,645,111
Deferred tax liabilities, net	70,719	100,361
Non-current tax liabilities	54,042	88,667
Other liabilities	524,026	430,577
Total Liabilities	7,722,342	8,258,873
Commitments and contingencies
CBRE Group, Inc. Stockholders' Equity	3,014,487	2,712,652
Non-controlling interests	42,758	46,418
Total Equity	3,057,245	2,759,070	2,301,398	1,936,006
Total Liabilities and Equity	10,779,587	11,017,943
Eliminations [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Income taxes receivable	(19,279)	(32,277)
Total Current Assets	(19,279)	(32,277)
Investments in consolidated subsidiaries	(10,617,443)	(9,857,027)
Intercompany loan receivable	(3,384,421)	(3,290,949)
Deferred tax assets, net	(57,335)	(39,473)
Total Assets	(14,078,478)	(13,219,726)
Income taxes payable	(19,279)	(32,277)
Total Current Liabilities	(19,279)	(32,277)
Intercompany loan payable	(3,384,421)	(3,290,949)
Total long-term debt, net	(3,384,421)	(3,290,949)
Deferred tax liabilities, net	(57,335)	(39,473)
Total Liabilities	(3,461,035)	(3,362,699)
Commitments and contingencies
CBRE Group, Inc. Stockholders' Equity	(10,617,443)	(9,857,027)
Total Equity	(10,617,443)	(9,857,027)
Total Liabilities and Equity	(14,078,478)	(13,219,726)
Parent [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents	7	5	5	5
Income taxes receivable	1,915	25,912
Total Current Assets	1,922	25,917
Investments in consolidated subsidiaries	4,226,629	3,699,642
Total Assets	4,228,551	3,725,559
Intercompany loan payable	1,214,064	1,012,907
Total long-term debt, net	1,214,064	1,012,907
Total Liabilities	1,214,064	1,012,907
Commitments and contingencies
CBRE Group, Inc. Stockholders' Equity	3,014,487	2,712,652
Total Equity	3,014,487	2,712,652
Total Liabilities and Equity	4,228,551	3,725,559
CBRE [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents	16,889	8,479	18,262	11,585
Income taxes receivable	17,364	6,365
Other current assets	1,421	9,236
Total Current Assets	35,674	24,080
Investments in consolidated subsidiaries	4,076,265	3,796,841
Intercompany loan receivable	2,684,421	2,590,949
Other assets, net	22,229	22,055
Total Assets	6,818,589	6,433,925
Accounts payable and accrued expenses	30,049	31,616
Compensation and employee benefits payable	626	626
Current maturities of long-term debt		34,375
Other current liabilities		1,063
Total Current Liabilities	30,675	67,680
Long-term debt, net	2,548,123	2,645,101
Total long-term debt, net	2,548,123	2,645,101
Other liabilities	13,162	21,502
Total Liabilities	2,591,960	2,734,283
Commitments and contingencies
CBRE Group, Inc. Stockholders' Equity	4,226,629	3,699,642
Total Equity	4,226,629	3,699,642
Total Liabilities and Equity	6,818,589	6,433,925
Guarantor Subsidiaries [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents	264,121	147,410	374,103	91,244
Restricted cash	6,967	6,421
Receivables, net	943,028	860,776
Warehouse receivables	687,454	1,397,094
Income taxes receivable	8,170	10,552
Prepaid expenses	78,296	77,109
Other current assets	64,576	62,386
Total Current Assets	2,052,612	2,561,748
Property and equipment, net	395,749	382,897
Goodwill	1,669,683	1,626,618
Other intangible assets, net	793,525	844,611
Investments in unconsolidated subsidiaries	189,455	184,508
Investments in consolidated subsidiaries	2,314,549	2,360,544
Intercompany loan receivable	700,000	700,000
Deferred tax assets, net	72,325	68,971
Other assets, net	240,707	176,835
Total Assets	8,428,605	8,906,732
Accounts payable and accrued expenses	409,470	395,509
Compensation and employee benefits payable	402,719	388,251
Accrued bonus and profit sharing	506,715	479,106
Income taxes payable	40,946	69,121
Warehouse lines of credit (which fund loans that U.S. Government Sponsored Entities have committed to purchase)	680,473	1,388,033
Other	16	16
Total short-term borrowings	680,489	1,388,049
Other current liabilities	81,590	31,474
Total Current Liabilities	2,121,929	2,751,510
Intercompany loan payable	1,916,675	2,043,433
Total long-term debt, net	1,916,675	2,043,433
Non-current tax liabilities	53,422	87,483
Other liabilities	260,314	227,465
Total Liabilities	4,352,340	5,109,891
Commitments and contingencies
CBRE Group, Inc. Stockholders' Equity	4,076,265	3,796,841
Total Equity	4,076,265	3,796,841
Total Liabilities and Equity	8,428,605	8,906,732
Nonguarantor Subsidiaries [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents	481,559	384,509	$ 348,514	$ 389,078
Restricted cash	61,869	66,343
Receivables, net	1,662,574	1,610,964
Warehouse receivables	588,593	370,013
Income taxes receivable	37,456	48,779
Prepaid expenses	105,811	95,813
Other current assets	113,659	149,334
Total Current Assets	3,051,521	2,725,755
Property and equipment, net	165,007	146,926
Goodwill	1,311,709	1,459,379
Other intangible assets, net	617,514	605,858
Investments in unconsolidated subsidiaries	42,783	33,435
Deferred tax assets, net	90,334	105,754
Other assets, net	103,452	94,346
Total Assets	5,382,320	5,171,453
Accounts payable and accrued expenses	1,006,919	1,056,994
Compensation and employee benefits payable	369,577	316,193
Accrued bonus and profit sharing	383,606	387,788
Income taxes payable	36,684	45,350
Warehouse lines of credit (which fund loans that U.S. Government Sponsored Entities have committed to purchase)	574,180	362,748
Total short-term borrowings	574,180	362,748
Current maturities of long-term debt	11	53
Other current liabilities	21,127	38,118
Total Current Liabilities	2,392,104	2,207,244
Long-term debt, net	3	10
Intercompany loan payable	253,682	234,609
Total long-term debt, net	253,685	234,619
Deferred tax liabilities, net	128,054	139,834
Non-current tax liabilities	620	1,184
Other liabilities	250,550	181,610
Total Liabilities	3,025,013	2,764,491
Commitments and contingencies
CBRE Group, Inc. Stockholders' Equity	2,314,549	2,360,544
Non-controlling interests	42,758	46,418
Total Equity	2,357,307	2,406,962
Total Liabilities and Equity	$ 5,382,320	$ 5,171,453