Acquisition (Tables)

3 Months Ended

Mar. 31, 2018

Business Acquisition [Line Items]

Business Acquisition, Pro Forma Information

	For the three months ended March 31, 2017
	(dollars in thousands, except per share data)
	(unaudited)
Revenues	$	162,773
Net income (loss) attributable to Cowen Inc. stockholders	(7,899		)
Net income (loss) per common share:
Basic	$	(0.26	)
Diluted	(0.26		)