Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Examination [Line Items]
Pre-tax income (loss) from foreign operations		$ (199,200,000)	$ 62,600,000
Pre-tax income (loss) from domestic operations	(30,000,000)		(6,900,000)
Operating loss carryforwards, expiration year description	The Company has net operating losses in various jurisdictions that will begin to expire in 2017.
Net operating loss expiration start year	2018
U.S. federal research and development credit carryforward expiration start year	2023
Unrecognized tax benefits	0	3,250,000	3,250,000
Accrued interest related to uncertain tax positions	0
Sale of eSpeed [Member]
Income Tax Examination [Line Items]
Pre-tax income (loss) from domestic operations		464,900,000
Global Partnership Restructuring Program [Member]
Income Tax Examination [Line Items]
Pre-tax income (loss) from foreign operations	$ 26,800,000