Earnings per Common Share (EPS) (Details) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021 USD ($) $ / shares shares	Jun. 30, 2020 USD ($) $ / shares shares	Jun. 30, 2021 USD ($) $ / shares shares	Jun. 30, 2020 USD ($) $ / shares shares
Earnings Per Share Reconciliation [Abstract]
Net loss from continuing operations | $	$ (2,420)	$ (694)	$ (14,786)	$ (4,044)
Net income (loss) attributable to redeemable noncontrolling interests | $	(50)	(165)	286	(182)
Preferred stock dividends | $	(21,476)	(9,289)	(32,006)	(18,197)
Net loss attributable to Synchronoss | $	(23,946)	(10,148)	(46,506)	(22,423)
Net loss from continuing operations attributable to Synchronoss | $	$ (23,946)	$ (10,148)	$ (46,506)	$ (22,423)
Denominator:
Weighted average common shares outstanding - basic (in shares)	44,131,000	41,697,000	43,438,000	41,482,000
Dilutive effect of:
Shares from assumed conversion of preferred stock (in shares)	0	0	0	0
Shares from assumed conversion of Performance Based Cash Units (in shares)	0	0	0	0
Weighted average common shares outstanding - diluted (in shares)	44,131,000	41,697,000	43,438,000	41,482,000
Earnings per share:
Basic (in dollars per share) | $ / shares	$ (0.54)	$ (0.24)	$ (1.07)	$ (0.54)
Diluted (in dollars per share) | $ / shares	$ (0.54)	$ (0.24)	$ (1.07)	$ (0.54)
Stock Options
Earnings per share:
Anti-dilutive stock options excluded (in shares)	0	0	0	0
Restricted Stock Awards
Earnings per share:
Anti-dilutive stock options excluded (in shares)	2,586,000	2,220,000	2,586,000	2,220,000
Preferred Stock
Earnings per share:
Anti-dilutive stock options excluded (in shares)	14,939,846	12,956,487	14,679,984	12,729,876
Preferred stock, conversion ratio			0.0555556
Performance Based Cash Units
Earnings per share:
Anti-dilutive stock options excluded (in shares)	826,742	0	699,023	0
Performance based cash units, conversion ratio			1