Net Capital Requirements and Customer Protection Requirements - Net Capital Requirements and Customer Protection Requirements (Detail) (USD $)	Dec. 31, 2013
Adjusted Capital Requirements And Customer Protection Requirements [Line Items]
Minimum net capital required	$ 250,000
MarketAxess Corporation [Member]
Adjusted Capital Requirements And Customer Protection Requirements [Line Items]
Net capital	86,367,000
Minimum net capital required	1,859,000
Excess net capital	84,508,000
MarketAxess Europe Limited [Member]
Adjusted Capital Requirements And Customer Protection Requirements [Line Items]
Net capital	17,792,000
Minimum net capital required	3,227,000
Excess net capital	14,565,000
Marketaxess Canada Company [Member]
Adjusted Capital Requirements And Customer Protection Requirements [Line Items]
Net capital	865,000
Minimum net capital required	259,000
Excess net capital	$ 606,000