Quarterly Selected Financial Data (as Restated) (Unaudited) - Reconciliation of Unaudited Interim Condensed Consolidated Balance Sheets (Details) - USD ($)	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Mar. 20, 2019	[1]	Mar. 19, 2019	Dec. 31, 2018	Dec. 31, 2017
Warrants and rights Outstanding	$ 16,150,379	$ 61,300,000	$ 36,200,000	$ 5,600,000	$ 16,498,900	$ 46,900,000	$ 47,500,000	$ 43,900,000
Total liabilities	381,451,000	338,816,000	319,419,000	299,482,000	333,201,000	316,517,000	329,727,000	330,535,000
Additional paid-in capital	649,540,000	634,722,000	633,612,000	607,289,000	616,888,000	619,135,000	619,010,000	619,010,000
Accumulated deficit	(323,246,000)	(250,485,000)	(202,938,000)	(183,631,000)	(35,269,000)	(27,412,000)	(30,374,000)	(30,383,000)
Total OneSpaWorld shareholders' equity	320,828,000	378,459,000	424,414,000	417,897,000	582,344,000	591,398,000	588,251,000	588,372,000
Total shareholders' equity	320,828,000	378,459,000	424,414,000	417,897,000	590,468,000	599,384,000	594,929,000	594,100,000	$ 633,590,000		$ 199,006,000	$ (127,583,000)	$ 225,281,000
As Reported [Member]
Total liabilities	276,751,000	277,516,000	283,219,000	293,882,000	277,301,000	269,617,000	282,227,000	286,635,000
Additional paid-in capital	727,054,000	713,622,000	712,512,000	643,489,000	653,088,000	655,335,000	655,210,000	655,210,000
Accumulated deficit	(296,060,000)	(268,085,000)	(245,638,000)	(214,231,000)	(15,569,000)	(16,712,000)	(19,074,000)	(22,683,000)
Total OneSpaWorld shareholders' equity		439,759,000	460,614,000	423,497,000	638,244,000	638,298,000	635,751,000	632,272,000
Total shareholders' equity	425,528,000	439,759,000	460,614,000	423,497,000	646,368,000	646,284,000	642,429,000	638,000,000
Restatement Impact [Member]
Warrants and rights Outstanding		61,300,000	36,200,000	5,600,000		46,900,000	47,500,000	43,900,000
Total liabilities	104,700,000	61,300,000	36,200,000	5,600,000	55,900,000	46,900,000	47,500,000	43,900,000
Additional paid-in capital	(77,514,000)	(78,900,000)	(78,900,000)	(36,200,000)	(36,200,000)	(36,200,000)	(36,200,000)	(36,200,000)
Accumulated deficit	(27,186,000)	17,600,000	42,700,000	30,600,000	(19,700,000)	(10,700,000)	(11,300,000)	(7,700,000)
Total OneSpaWorld shareholders' equity		(61,300,000)	(36,200,000)	(5,600,000)	(55,900,000)	(46,900,000)	(47,500,000)	(43,900,000)
Total shareholders' equity	$ (104,700,000)	$ (61,300,000)	$ (36,200,000)	$ (5,600,000)	$ (55,900,000)	$ (46,900,000)	$ (47,500,000)	$ (43,900,000)

[1] Initial equity balances of the Successor reflect the equity of the accounting acquirer, Haymaker Acquisition Corp., and the issuance of common stock, warrants and cash contributed by Haymaker in connection with the acquisition of OSW Predecessor.