Consolidated Statements of Stockholder's Equity (Deficit) - USD ($) $ in Thousands	Total	Common Stock	Treasury Stock	Additional Paid-In Capital	Accumulated Comprehensive Income (Loss)	Retained Earnings (Accumulated Deficit)	Alliance HealthCare Services, Inc.	Non-controlling Interest
Beginning balance at Dec. 31, 2012	$ (116,293)	$ 524	$ (2,877)	$ 21,507	$ (716)	$ (183,226)	$ (164,788)	$ 48,495
Beginning balance, shares at Dec. 31, 2012		10,615,072	(140,028)
Exercise of stock options	$ 527			527			527
Exercise of common stock options, shares	31,679	31,679
Forfeiture of restricted stock, shares		(7,334)
Release of vested restricted stock (shares)		27,719
Purchase of treasury stock	$ (121)		$ (121)				(121)
Purchase of treasury stock (shares)			(4,893)
Share-based payment	1,487			1,487			1,487
Unrealized gain (loss) on hedging transaction, net of tax	634				634		634
Net distributions	(14,409)							(14,409)
Net income (loss)	(8,442)					(21,483)	(21,483)	13,041
Ending balance at Dec. 31, 2013	(136,617)	$ 524	$ (2,998)	23,521	(82)	(204,709)	(183,744)	47,127
Ending balance, shares at Dec. 31, 2013		10,667,136	(144,921)
Exercise of stock options	$ 467	$ 1		466			467
Exercise of common stock options, shares	72,794	72,794
Forfeiture of restricted stock, shares		(26,272)
Purchase of treasury stock	$ (140)		$ (140)				(140)
Purchase of treasury stock (shares)			(13,052)
Share-based payment	1,515			1,515			1,515
Share-based payment income tax benefit (detriment)	82			82			82
Unrealized gain (loss) on hedging transaction, net of tax	(269)				(269)		(269)
Noncontrolling interest disposed in connection with acquisition	1,651			1,651			1,651
Net distributions	(3,670)							(3,670)
Other		$ (418)		418
Net income (loss)	25,501					10,618	10,618	14,883
Ending balance at Dec. 31, 2014	(111,480)	$ 107	$ (3,138)	27,653	(351)	(194,091)	(169,820)	58,340
Ending balance, shares at Dec. 31, 2014		10,713,658	(157,973)
Exercise of stock options	$ 25			25			25
Exercise of common stock options, shares	2,515	2,515
Release of vested restricted stock	$ 1	$ 1					1
Release of vested restricted stock (shares)		58,684
Share-based payment	1,701			1,701			1,701
Share-based payment income tax benefit (detriment)	(82)			(82)			(82)
Unrealized gain (loss) on hedging transaction, net of tax	(160)				(160)		(160)
Net investments in subsidiaries	16,304							16,304
Net income (loss)	27,115					6,742	6,742	20,373
Ending balance at Dec. 31, 2015	$ (66,576)	$ 108	$ (3,138)	$ 29,297	$ (511)	$ (187,349)	$ (161,593)	$ 95,017
Ending balance, shares at Dec. 31, 2015		10,774,857	(157,973)