Business Segment Information - Financial Information Regarding Company's Operations by Geographic Area (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Segment Reporting Information [Line Items]
Revenues from unaffiliated customers	$ 1,532,957	$ 1,531,664	$ 1,504,952	$ 1,411,370	$ 1,501,914	$ 1,606,368	$ 1,581,368	$ 1,460,848	$ 5,980,943	$ 6,150,498	$ 5,967,573
Total revenues									5,980,943	6,150,498	5,967,573
Net revenues	458,738	465,138	453,651	446,571	476,155	493,846	472,561	453,915	1,824,098	1,896,477	1,692,786
Operating income									530,798	618,327	547,230
Identifiable assets at year end	2,954,125				2,866,827				2,954,125	2,866,827	2,679,179
Capital expenditures									47,626	78,115	42,408
Depreciation and amortization									39,940	36,776	36,900
Equity	2,032,570				2,010,069				2,032,570	2,010,069	1,748,154	1,561,347
United States
Segment Reporting Information [Line Items]
Revenues from unaffiliated customers									1,519,276	1,540,477	1,348,259
Transfers between geographic areas									94,521	101,738	99,547
Total revenues									1,613,797	1,642,215	1,447,806
Net revenues									737,679	732,299	666,669
Operating income									179,015	210,702	198,393
Identifiable assets at year end	1,459,425				1,521,657				1,459,425	1,521,657	1,343,098
Capital expenditures									28,088	23,219	18,128
Depreciation and amortization									23,678	20,037	20,125
Equity	1,197,239				1,285,812				1,197,239	1,285,812	1,089,053
Other North America
Segment Reporting Information [Line Items]
Revenues from unaffiliated customers									201,521	189,843	163,750
Transfers between geographic areas									10,476	11,095	10,836
Total revenues									211,997	200,938	174,586
Net revenues									95,798	90,432	77,079
Operating income									32,385	29,209	23,521
Identifiable assets at year end	92,075				86,020				92,075	86,020	95,298
Capital expenditures									832	1,122	574
Depreciation and amortization									756	1,038	1,344
Equity	58,071				49,571				58,071	49,571	46,601
Latin America
Segment Reporting Information [Line Items]
Revenues from unaffiliated customers									82,337	82,312	74,327
Transfers between geographic areas									18,780	21,222	16,932
Total revenues									101,117	103,534	91,259
Net revenues									57,795	59,968	50,937
Operating income									17,356	19,151	15,985
Identifiable assets at year end	48,995				48,221				48,995	48,221	51,326
Capital expenditures									1,301	628	1,320
Depreciation and amortization									873	999	880
Equity	29,504				27,346				29,504	27,346	27,462
Asia Pacific
Segment Reporting Information [Line Items]
Revenues from unaffiliated customers									3,074,587	3,144,641	3,349,960
Transfers between geographic areas									43,721	40,012	32,837
Total revenues									3,118,308	3,184,653	3,382,797
Net revenues									551,211	605,151	543,869
Operating income									216,559	258,952	222,944
Identifiable assets at year end	776,902				667,171				776,902	667,171	612,085
Capital expenditures									11,275	25,295	5,743
Depreciation and amortization									6,810	7,243	7,511
Equity	538,710				448,613				538,710	448,613	371,610
Europe and Africa
Segment Reporting Information [Line Items]
Revenues from unaffiliated customers									816,927	891,185	729,022
Transfers between geographic areas									38,791	43,359	40,778
Total revenues									855,718	934,544	769,800
Net revenues									286,264	307,471	264,663
Operating income									59,314	72,248	63,115
Identifiable assets at year end	428,053				401,518				428,053	401,518	432,019
Capital expenditures									4,323	25,856	14,383
Depreciation and amortization									5,994	5,414	4,661
Equity	167,752				145,998				167,752	145,998	160,428
Middle East and India
Segment Reporting Information [Line Items]
Revenues from unaffiliated customers									286,295	302,040	302,255
Transfers between geographic areas									18,128	17,897	16,184
Total revenues									304,423	319,937	318,439
Net revenues									95,351	101,156	89,569
Operating income									26,169	28,065	23,272
Identifiable assets at year end	147,871				141,379				147,871	141,379	144,043
Capital expenditures									1,807	1,995	2,260
Depreciation and amortization									1,829	2,045	2,379
Equity	74,950				85,605				74,950	85,605	84,456
Eliminations
Segment Reporting Information [Line Items]
Transfers between geographic areas									(224,417)	(235,323)	(217,114)
Total revenues									(224,417)	(235,323)	(217,114)
Identifiable assets at year end	804				861				804	861	1,310
Equity	$ (33,656)				$ (32,876)				$ (33,656)	$ (32,876)	$ (31,456)