Quarterly Financial Information (unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2016		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
Quarterly Financial Information (unaudited) [Abstract]
Revenues	$ 124,933	[1]	$ 125,049		$ 125,003		$ 126,012		$ 113,482		$ 113,536		$ 113,425		$ 111,649		$ 500,998	$ 452,092	$ 405,263
Gross margin	38,304	[1]	34,562		34,590		33,105		30,748		33,078		34,711		30,146
Income before income taxes	20,972	[1]	17,925		19,962		19,208		16,063		21,383		17,698		17,775		78,064	72,919	70,394
Net income from continuing operations attributable to Tivity Health, Inc.	12,125	[1]	4,799		19,962		19,208		9,238		12,960		10,756		10,680		56,091	43,634	42,836
Net income (loss) from discontinued operations attributable to Tivity Health, Inc.	(5,225)	[1]	48,995		(195,558)		(33,417)		(28,666)		(21,986)		(10,336)		(13,593)		(185,202)	(74,581)	(48,397)
Net income (loss) attributable to Tivity Health, Inc.	$ 6,900	[1]	$ 53,794		$ (175,596)		$ (14,209)		$ (19,428)		$ (9,026)		$ 420		$ (2,913)		$ (129,111)	$ (30,947)	$ (5,561)
Earnings (loss) per share attributable to Tivity Health, Inc. - basic [Abstract]
Continuing operations (in dollars per share)	$ 0.31	[1],[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)	[1],[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 income (loss) (dollars per share)	0.18	[1],[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	[1],[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)	[1],[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 income (loss) (dollars per share)	$ 0.17	[1],[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)
Impact of adjustment amount due to decrease in depreciation expense on net income from continuing operations	$ 2,200

[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.