Earnings (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2016	[1]	Sep. 30, 2016		Jun. 30, 2016		Mar. 31, 2016		Dec. 31, 2015		Sep. 30, 2015		Jun. 30, 2015		Mar. 31, 2015		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Numerator [Abstract]
Net income from continuing operations attributable to Tivity Health, Inc. - numerator for earnings per share	$ 12,125		$ 4,799		$ 19,962		$ 19,208		$ 9,238		$ 12,960		$ 10,756		$ 10,680		$ 56,091	$ 43,634	$ 42,836
Net loss from discontinued operations attributable to Tivity Health, Inc. - numerator for loss per share	(5,225)		48,995		(195,558)		(33,417)		(28,666)		(21,986)		(10,336)		(13,593)		(185,202)	(74,581)	(48,397)
Net loss attributable to Tivity Health, Inc.	$ 6,900		$ 53,794		$ (175,596)		$ (14,209)		$ (19,428)		$ (9,026)		$ 420		$ (2,913)		$ (129,111)	$ (30,947)	$ (5,561)
Denominator [Abstract]
Shares used for basic income (loss) per share (in shares)																	36,999	35,832	35,302
Effect of dilutive stock options and restricted stock units outstanding [Abstract]
Shares used for diluted income (loss) per share (in shares)																	38,075	36,854	36,346
Earnings (loss) per share attributable to Tivity Health, Inc. - basic [Abstract]
Continuing operations (in dollars per share)	$ 0.31	[2]	$ 0.13	[2]	$ 0.55	[2]	$ 0.53	[2]	$ 0.26	[2]	$ 0.36	[2]	$ 0.30	[2]	$ 0.30	[2]	$ 1.52	$ 1.22	$ 1.21
Discontinued operations (in dollars per share)	(0.14)	[2]	1.32	[2]	(5.41)	[2]	(0.93)	[2]	(0.79)	[2]	(0.61)	[2]	(0.29)	[2]	(0.38)	[2]	(5.01)	(2.08)	(1.37)
Net loss (in dollars per share)	0.18	[2],[3]	1.45	[2],[3]	(4.85)	[2],[3]	(0.39)	[2],[3]	(0.54)	[2],[3]	(0.25)	[2],[3]	0.01	[2],[3]	(0.08)	[2],[3]	(3.49)	(0.86)	(0.16)
Earnings (loss) per share attributable to Tivity Health, Inc. - diluted [Abstract]
Continuing operations (in dollars per share)	0.30	[2]	0.12	[2]	0.54	[2]	0.52	[2]	0.25	[2]	0.35	[2]	0.29	[2]	0.29	[2]	1.47	1.18	1.18
Discontinued operations (in dollars per share)	(0.13)	[2]	1.28	[2]	(5.25)	[2]	(0.91)	[2]	(0.78)	[2]	(0.60)	[2]	(0.28)	[2]	(0.37)	[2]	(4.86)	(2.02)	(1.33)
Net loss (in dollars per share)	$ 0.17	[2],[3]	$ 1.40	[2],[3]	$ (4.72)	[2],[3]	$ (0.39)	[2],[3]	$ (0.53)	[2],[3]	$ (0.25)	[2],[3]	$ 0.01	[2],[3]	$ (0.08)	[2],[3]	$ (3.39)	$ (0.84)	$ (0.15)
Non-Qualified Stock Options [Member]
Effect of dilutive stock options and restricted stock units outstanding [Abstract]
Effect of dilutive stock options and restricted stock units outstanding (in shares)																	344	568	706
Restricted Stock Units [Member]
Effect of dilutive stock options and restricted stock units outstanding [Abstract]
Effect of dilutive stock options and restricted stock units outstanding (in shares)																	538	364	313
Performance Stock Units [Member]
Effect of dilutive stock options and restricted stock units outstanding [Abstract]
Effect of dilutive stock options and restricted stock units outstanding (in shares)																	0	25	21
Market Stock Units [Member]
Effect of dilutive stock options and restricted stock units outstanding [Abstract]
Effect of dilutive stock options and restricted stock units outstanding (in shares)																	194	10	0
CareFirst Warrants [Member]
Effect of dilutive stock options and restricted stock units outstanding [Abstract]
Effect of dilutive stock options and restricted stock units outstanding (in shares)																	0	55	4
Non-Qualified Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive securities outstanding not included in the computation of earnings (loss) per share because their effect is anti-dilutive (in shares)																	708	903	1,357
Restricted Stock Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive securities outstanding not included in the computation of earnings (loss) per share because their effect is anti-dilutive (in shares)																	333	220	97
Performance Stock Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive securities outstanding not included in the computation of earnings (loss) per share because their effect is anti-dilutive (in shares)																	0	0	1
Market Stock Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive securities outstanding not included in the computation of earnings (loss) per share because their effect is anti-dilutive (in shares)																	6	2	0
Warrants Related to Cash Convertible Notes [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive securities outstanding not included in the computation of earnings (loss) per share because their effect is anti-dilutive (in shares)																	7,707	7,707	7,707
CareFirst Convertible Note [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive securities outstanding not included in the computation of earnings (loss) per share because their effect is anti-dilutive (in shares)																	0	892	892
CareFirst Warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive securities outstanding not included in the computation of earnings (loss) per share because their effect is anti-dilutive (in shares)																	0	263	83

[1] Net income from continuing operations includes the impact of a $2.2 million adjustment recorded in the fourth quarter to decrease depreciation expense (with a corresponding increase to depreciation expense from discontinued operations) related to the revision of an estimate based on having completed our asset separation analysis.

[2] We calculated earnings per share for each of the quarters based on the weighted average number of shares and dilutive securities outstanding for each period. Accordingly, the sum of the quarters may not necessarily be equal to the full year income per share.

[3] Figures may not add due to rounding.