Earnings Per Share of Common Stock (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Basic and Diluted Earnings (Loss) Per Share of Common Stock [Abstract]
Net income (loss) attributable to Broadridge Financial Corporation	$ 701	$ 216	$ (2,786)	$ 183
Less net income (loss) attributable to participating securities	0	2	0	2
Income (loss) available to common stockholders	$ 701	$ 214	$ (2,786)	$ 181
Weighted average common shares outstanding for basic earnings (loss) per common share (in shares)	70,163,639	27,143,340	48,873,496	27,055,750
Add: dilutive effects of unvested restricted stock awards (in shares)	140,247	307,376	0	337,097
Weighted average common shares outstanding for diluted earnings (loss) per common share (in shares)	70,303,886	27,450,716	48,873,496	27,392,847
Earnings (loss) per common share - basic (in dollars per share)	$ 0.01	$ 0.01	$ (0.06)	$ 0.01
Earnings (loss) per common share - diluted (in dollars per share)	$ 0.01	$ 0.01	$ (0.06)	$ 0.01
Stock Options [Member]
Earnings Per Share of Common Stock [Abstract]
Anti-dilutive stock not considered in computing diluted earnings per common share (in shares)			450,000
Unvested Restricted Stock Awards [Member]
Earnings Per Share of Common Stock [Abstract]
Anti-dilutive stock not considered in computing diluted earnings per common share (in shares)	0