Acquisition (Tables)

9 Months Ended

Sep. 30, 2018

Business Combinations [Abstract]

Business Acquisition, Pro Forma Information

	Nine Months Ended September 30, 2017
	(dollars in thousands, except per share data)
	(unaudited)
Revenues	$	529,294
Net income (loss) attributable to Cowen Inc. stockholders	(7,001		)
Net income (loss) per common share:
Basic	$	(0.23	)
Diluted	(0.23		)