Stockholders' Deficit (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Increase (Decrease) in Stockholders' Deficit [Roll Forward]
Beginning balance			$ (111,480)
Exercise of stock options (shares)			2,515	67,657
Exercise of stock options			$ 25
Share-based payment			819
Share-based payment income tax benefit			(82)
Unrealized loss on hedging transaction, net of tax			(141)
Net investments in subsidiaries			12,246
Net income (loss)	$ 2,942	$ 6,820	9,040	$ 11,800
Ending balance	$ (89,573)		$ (89,573)
Common Stock
Increase (Decrease) in Stockholders' Deficit [Roll Forward]
Beginning balance (shares)			10,713,658
Beginning balance			$ 107
Exercise of stock options (shares)			2,515
Ending balance (shares)	10,716,173		10,716,173
Ending balance	$ 107		$ 107
Treasury Stock
Increase (Decrease) in Stockholders' Deficit [Roll Forward]
Beginning balance (shares)			157,973
Beginning balance			$ (3,138)
Ending balance (shares)	157,973		157,973
Ending balance	$ (3,138)		$ (3,138)
Additional Paid-In Capital
Increase (Decrease) in Stockholders' Deficit [Roll Forward]
Beginning balance			27,653
Exercise of stock options			25
Share-based payment			819
Share-based payment income tax benefit			(82)
Ending balance	28,415		28,415
Accumulated Comprehensive Income (Loss)
Increase (Decrease) in Stockholders' Deficit [Roll Forward]
Beginning balance			(351)
Unrealized loss on hedging transaction, net of tax			(141)
Ending balance	(492)		(492)
Accumulated Deficit
Increase (Decrease) in Stockholders' Deficit [Roll Forward]
Beginning balance			(194,091)
Net income (loss)			(210)
Ending balance	(194,301)		(194,301)
Alliance HealthCare Services, Inc.
Increase (Decrease) in Stockholders' Deficit [Roll Forward]
Beginning balance			(169,820)
Exercise of stock options			25
Share-based payment			819
Share-based payment income tax benefit			(82)
Unrealized loss on hedging transaction, net of tax			(141)
Net income (loss)			(210)
Ending balance	(169,409)		(169,409)
Noncontrolling Interest
Increase (Decrease) in Stockholders' Deficit [Roll Forward]
Beginning balance			58,340
Net investments in subsidiaries			12,246
Net income (loss)			9,250
Ending balance	$ 79,836		$ 79,836