Consolidated Statements of Operations and Comprehensive Income (Loss) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Statement [Abstract]
Revenues	$ 473,054	$ 436,387	$ 448,831
Costs and expenses:
Cost of revenues, excluding depreciation and amortization	269,104	237,420	239,397
Selling, general and administrative expenses	88,471	79,903	80,215
Transaction costs	3,296	2,344	465
Shareholder transaction costs	1,853
Severance and related costs	1,347	2,517	1,658
Impairment charges	6,817	308	13,031
Loss on extinguishment of debt			26,018
Depreciation expense	48,595	54,971	66,319
Amortization expense	9,325	7,880	10,973
Interest expense and other, net	26,241	24,693	39,170
Other (income) and expense, net	(12,255)	(1,823)	(1,945)
Total costs and expenses	442,794	408,213	475,301
Income (loss) before income taxes, earnings from unconsolidated investees, and noncontrolling interest	30,260	28,174	(26,470)
Income tax expense (benefit)	6,536	7,327	(12,398)
Earnings from unconsolidated investees	(3,391)	(4,654)	(5,630)
Net income (loss)	27,115	25,501	(8,442)
Less: Net income attributable to noncontrolling interest	(20,373)	(14,883)	(13,041)
Net income (loss) attributable to Alliance HealthCare Services, Inc.	6,742	10,618	(21,483)
Comprehensive income (loss), net of taxes:
Net income (loss) attributable to Alliance HealthCare Services, Inc.	6,742	10,618	(21,483)
Unrealized (loss) gain on hedging transactions, net of taxes	(160)	(269)	634
Comprehensive (loss) income, net of taxes:	$ 6,582	$ 10,349	$ (20,849)
Income (loss) per common share attributable to Alliance HealthCare Services, Inc.:
Basic	$ 0.63	$ 1.00	$ (2.02)
Diluted	$ 0.62	$ 0.98	$ (2.02)
Weighted-average number of shares of common stock and common stock equivalents:
Basic	10,741	10,669	10,634
Diluted	10,849	10,836	10,634