Business Segment Information - People's Republic of China Including Hong Kong Percentage Share of the Company's Total Revenue, Net Revenue, Total Identifiable Assets or Equity (Detail)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Total revenues | People's Republic of China, including Hong Kong
Concentration Risk [Line Items]
Concentration percentage	34.00%	34.00%	37.00%
Net revenues | People's Republic of China, including Hong Kong
Concentration Risk [Line Items]
Concentration percentage	16.00%	19.00%	19.00%
Identifiable assets at year end | People's Republic of China, including Hong Kong
Concentration Risk [Line Items]
Concentration percentage	17.00%	14.00%	13.00%
Equity | People's Republic of China, including Hong Kong
Concentration Risk [Line Items]
Concentration percentage	16.00%	13.00%	10.00%
Lower end | Geographic Concentration Risk
Concentration Risk [Line Items]
Concentration percentage	10.00%