CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Treasury Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Treasury Stock	Treasury Stock Treasury Stock	Treasury Stock Additional Paid-In Capital	Common Stock	Common Stock Common Stock	Common Stock Additional Paid-In Capital
Balance (As Previously Reported) at Dec. 31, 2014	$ 529,107	$ 4	$ (66,336)	$ 454,740	$ (20,014)	$ 160,713
Balance (Adjustments)	(65,643)		(1,991)	2,408	1,560	(67,620)
Balance at Dec. 31, 2014	463,464	$ 4	$ (68,327)	457,148	(18,454)	93,093
Balance (in shares) (As Previously Reported) at Dec. 31, 2014		46,444	(3,733)
Balance (in shares) (Adjustments)		176	(159)
Balance (in shares) at Dec. 31, 2014		46,620	(3,892)
Increase (Decrease) in Stockholders' Equity
Stock based compensation	30,780			30,780
Issuance of restricted stock	0			0
Issuance of restricted stock (in shares)		(734)
Issuance of common stock on exercise of options	19,936			19,936
Issuance of common stock on exercise of options (in shares)		879
ESPP compensation	624			624
Sale of treasury stock in connection with an employee stock purchase plan	1,902			1,902
Other	0			4
Sale of treasury stock in connection with an employee stock purchase plan		54
Adjustments to redemption value of noncontrolling interest	(628)			(628)
Net income (loss) attributable to Synchronoss (2) | As Previously Reported	40,630
Net income (loss) attributable to Synchronoss (2)	3,113					3,113
Total other comprehensive income (loss) | As Previously Reported	(18,670)
Total other comprehensive income (loss)	(19,060)				(19,060)
Tax benefit from stock option exercise	5,198			5,198
Balance at Dec. 31, 2015	505,329	$ 4	$ (68,327)	514,964	(37,514)	96,202
Balance (in shares) at Dec. 31, 2015		48,287	(3,892)
Increase (Decrease) in Stockholders' Equity
Cumulative effect of adjustment to retained earnings (ASU Adoption)	234			710		(476)
Net income (loss) attributable to Synchronoss (2) | As Previously Reported	(7,954)
Net income (loss) attributable to Synchronoss (2)	(29,329)
Balance (As Previously Reported) at Mar. 31, 2016	627,716
Balance at Mar. 31, 2016	497,963
Balance at Dec. 31, 2015	505,329	$ 4	$ (68,327)	514,964	(37,514)	96,202
Balance (in shares) at Dec. 31, 2015		48,287	(3,892)
Increase (Decrease) in Stockholders' Equity
Stock based compensation	33,361			33,361
Issuance of restricted stock	0			0
Issuance of restricted stock (in shares)		(585)
Issuance of common stock on exercise of options	13,913	$ 1		13,912
Issuance of common stock on exercise of options (in shares)		608
ESPP compensation	817			817
Issuance of common stock related to acquisition	22,000			22,000
Issuance of common stock related to acquisition (in shares)		840
Issuance of common stock to subsidiary (in shares)		20
Sale of treasury stock in connection with an employee stock purchase plan	(40,025)		$ (40,025)
Repurchase of treasury stock (in shares)			(1,262)
Sale of treasury stock in connection with an employee stock purchase plan							$ 1,228	$ 1,721	$ (493)	$ 955		$ 955
Other	130			130
Sale of treasury stock in connection with an employee stock purchase plan								58
Adjustments to redemption value of noncontrolling interest	(15,203)			(15,203)
Net income (loss) attributable to Synchronoss (2) | As Previously Reported	19,588
Net income (loss) attributable to Synchronoss (2)	11,894					11,894
Total other comprehensive income (loss) | As Previously Reported	(4,569)
Total other comprehensive income (loss)	(4,836)				(4,836)
Balance (As Previously Reported) at Dec. 31, 2016	657,115
Balance at Dec. 31, 2016	$ 529,797	$ 5	$ (106,631)	571,153	(42,350)	107,620
Balance (in shares) at Dec. 31, 2016	50,388	50,388	(5,096)
Balance (As Previously Reported) at Mar. 31, 2016	$ 627,716
Balance at Mar. 31, 2016	497,963
Increase (Decrease) in Stockholders' Equity
Net income (loss) attributable to Synchronoss (2) | As Previously Reported	(4,439)
Net income (loss) attributable to Synchronoss (2)	7,832
Balance (As Previously Reported) at Jun. 30, 2016	605,754
Balance at Jun. 30, 2016	485,489
Increase (Decrease) in Stockholders' Equity
Net income (loss) attributable to Synchronoss (2) | As Previously Reported	7,676
Net income (loss) attributable to Synchronoss (2)	(2,667)
Balance (As Previously Reported) at Sep. 30, 2016	631,172
Balance at Sep. 30, 2016	502,896
Increase (Decrease) in Stockholders' Equity
Net income (loss) attributable to Synchronoss (2) | As Previously Reported	24,305
Net income (loss) attributable to Synchronoss (2)	36,058
Balance (As Previously Reported) at Dec. 31, 2016	657,115
Balance at Dec. 31, 2016	$ 529,797	$ 5	$ (106,631)	571,153	(42,350)	107,620
Balance (in shares) at Dec. 31, 2016	50,388	50,388	(5,096)
Increase (Decrease) in Stockholders' Equity
Cumulative effect of adjustment to retained earnings (ASU Adoption)	$ (3,196)					(3,196)
Stock based compensation	28,446			28,446
Issuance of restricted stock	0
Issuance of restricted stock (in shares)		(1,565)
Issuance of common stock on exercise of options	$ 2,460			2,460
Issuance of common stock on exercise of options (in shares)	104	104
ESPP compensation	$ 495			495
Issuance of common stock related to acquisition	4,701			4,701
Sale of treasury stock in connection with an employee stock purchase plan	1,047		$ 1,047
Shares withheld for taxes in connection with issuance of restricted stock		29
Shares withheld for taxes in connection with issuance of restricted stock	(442)			(442)
Other	31			31
Sale of treasury stock in connection with an employee stock purchase plan			36								48
Adjustments to redemption value of noncontrolling interest	(9,291)			(9,291)
Net income (loss) attributable to Synchronoss (2)	(109,438)					(109,438)
Total other comprehensive income (loss)	18,977				18,977
Balance at Dec. 31, 2017	$ 463,587	$ 5	$ (105,584)	$ 597,553	$ (23,373)	$ (5,014)
Balance (in shares) at Dec. 31, 2017	52,024	52,028	(5,060)