Acquisitions and Transactions - Additional Information (Details) $ / shares in Units, $ in Thousands				1 Months Ended	3 Months Ended								12 Months Ended
	Dec. 31, 2015 USD ($)	Oct. 14, 2015 USD ($) Location	Feb. 17, 2015 USD ($) Location Stage	Nov. 30, 2014 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2014 USD ($)	Jun. 30, 2014 USD ($)	Mar. 31, 2014 USD ($)	Dec. 31, 2015 USD ($) $ / shares	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Aug. 01, 2015	Jul. 31, 2015
Restructuring Cost and Reserve [Line Items]
Payments to acquire businesses, net of cash													$ 49,140	$ 16,043
Transaction and other integration costs													3,300
Net revenue generated from acquisition													$ 43,800
Ownership interest, percentage acquired	15.50%				15.50%								15.50%
Goodwill	$ 102,782				$ 102,782				$ 63,864				$ 102,782	63,864	$ 56,975
Contingent consideration related to acquisition	5,750				5,750								5,750
Mandatorily redeemable noncontrolling interest	2,386				2,386								2,386
Ownership interest by parent																65.50%
Non-cash gain on step acquisition													10,672
Intangible assets	$ 162,923				162,923				115,930				162,923	115,930
Revenues					124,337	$ 120,784	$ 118,504	$ 109,429	109,647	$ 110,137	$ 111,238	$ 105,365	473,054	436,387	448,831
Net income (loss)					$ 5,010	$ 13,065	$ 2,942	$ 6,098	$ 5,847	$ 7,854	$ 6,820	$ 4,980	27,115	25,501	(8,442)
Restructuring charges													1,327	2,602	7,182
Impairment of intangible assets													6,817	308	13,031
Professional Radiology Services
Restructuring Cost and Reserve [Line Items]
Intangible assets															1,525
Impairment of intangible assets															5,107
Selling, General and Administrative Expenses
Restructuring Cost and Reserve [Line Items]
Restructuring charges													175	1,162	4,990
Amortization
Restructuring Cost and Reserve [Line Items]
Restructuring charges													225
Severance and Related Costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges													27	180	1,658
Cost of Revenues Excluding Depreciation and Amortization
Restructuring Cost and Reserve [Line Items]
Restructuring charges													$ 900	1,440	$ 534
Minimum
Restructuring Cost and Reserve [Line Items]
Percentage of ownership from investees (percent)	15.00%				15.00%								15.00%
Maximum
Restructuring Cost and Reserve [Line Items]
Percentage of ownership from investees (percent)	50.00%				50.00%								50.00%
Alliance-HNV PET/CT Services, LLC (AHNVPS)
Restructuring Cost and Reserve [Line Items]
Percentage of ownership from investees (percent)																	46.60%
Alliance-HNV PET/CT Services, LLC (AHNVPS) Not Consolidate
Restructuring Cost and Reserve [Line Items]
Ownership interest by parent																	53.40%
Pacific Cancer Institute Inc (PCI)
Restructuring Cost and Reserve [Line Items]
Payments to acquire businesses, net of cash	$ 11,013
Ownership interest, percentage acquired	95.00%				95.00%								95.00%
Goodwill	$ 5,890				$ 5,890								$ 5,890
Identifiable intangible assets	8,800				8,800								$ 8,800
Useful life													15 years
Weighted average useful life													15 years
Noncontrolling interest, fair value	430				430								$ 430
Contingent consideration performance period													12 months
Contingent consideration related to acquisition	1,450				1,450								$ 1,450
Pacific Cancer Institute Inc (PCI) | Physician referral network intangible assets
Restructuring Cost and Reserve [Line Items]
Identifiable intangible assets	1,800				1,800								1,800
Pacific Cancer Institute Inc (PCI) | Trademarks
Restructuring Cost and Reserve [Line Items]
Identifiable intangible assets	950				950								950
Pacific Cancer Institute Inc (PCI) | CON
Restructuring Cost and Reserve [Line Items]
Identifiable intangible assets	5,400				5,400								5,400
Pacific Cancer Institute Inc (PCI) | Non-Solicitation and Non-Competition Agreements
Restructuring Cost and Reserve [Line Items]
Identifiable intangible assets	650				650								650
AHIP Florida LLC
Restructuring Cost and Reserve [Line Items]
Payments to acquire businesses, net of cash		$ 15,014
Net revenue generated from acquisition													$ 3,126
Ownership interest, percentage acquired		60.00%
Goodwill		$ 7,806
Identifiable intangible assets		$ 15,400
Useful life		15 years
Weighted average useful life		15 years
Noncontrolling interest, fair value		$ 5,739
Contingent consideration performance period													12 months
Contingent consideration related to acquisition	2,500	$ 2,500			2,500								$ 2,500
Number of locations operated by entity | Location		8
Cash received		$ 264
Percentage of noncontrolling interest allowed to sell to the Company		10.00%
Mandatorily redeemable noncontrolling interest		$ 2,386
Net income generated from acquisition													357
AHIP Florida LLC | Physician referral network intangible assets
Restructuring Cost and Reserve [Line Items]
Identifiable intangible assets		12,600
AHIP Florida LLC | Trademarks
Restructuring Cost and Reserve [Line Items]
Identifiable intangible assets		1,700
AHIP Florida LLC | Non-Solicitation and Non-Competition Agreements
Restructuring Cost and Reserve [Line Items]
Identifiable intangible assets		$ 1,100
Alliance HNI LLC and Subsidiaries
Restructuring Cost and Reserve [Line Items]
Net revenue generated from acquisition													10,590
Ownership interest, percentage acquired																50.00%
Goodwill	2,988				2,988								2,988
Identifiable intangible assets	13,700				13,700								$ 13,700
Useful life													15 years
Noncontrolling interest, fair value	9,463				9,463								$ 9,463
Cash received	$ 1,848				$ 1,848								1,848
Net income generated from acquisition													$ 5,942
Equity interest in acquiree, percentage	50.00%				50.00%								50.00%
Capital required for capital adequacy to risk weighted assets	11.50%				11.50%								11.50%
Revenue multiple													1.7
Non-cash gain on step acquisition													$ 10,672
Alliance HNI LLC and Subsidiaries | Minimum
Restructuring Cost and Reserve [Line Items]
Earnings ratio multiple | $ / shares													$ 5.0
Alliance HNI LLC and Subsidiaries | Maximum
Restructuring Cost and Reserve [Line Items]
Earnings ratio multiple | $ / shares													$ 6.5
Alliance HNI LLC
Restructuring Cost and Reserve [Line Items]
Ownership interest, percentage acquired																15.50%
Alliance-HNI Leasing Co (AHNIL) | Alliance HNI LLC
Restructuring Cost and Reserve [Line Items]
Equity interest in acquiree, percentage																	98.00%
The Pain Center of Arizona
Restructuring Cost and Reserve [Line Items]
Payments to acquire businesses, net of cash			$ 24,088
Net revenue generated from acquisition													$ 30,067
Ownership interest, percentage acquired			59.00%
Goodwill			$ 22,566
Identifiable intangible assets			$ 24,600
Useful life			20 years
Weighted average useful life			15 years
Noncontrolling interest, fair value			$ 20,598
Contingent consideration performance period													12 months
Contingent consideration related to acquisition	$ 1,800		$ 1,800		$ 1,800								$ 1,800
Number of locations operated by entity | Location			12
Cash received			$ 234
Net income generated from acquisition													$ 1,794
Step acquisition, number of stages | Stage			2
Percentage of voting interests acquired before dilution			60.00%
Accounts receivable extinguishment, related parties			$ 3,071
The Pain Center of Arizona | Physician referral network intangible assets
Restructuring Cost and Reserve [Line Items]
Identifiable intangible assets			13,500
The Pain Center of Arizona | Trademarks
Restructuring Cost and Reserve [Line Items]
Identifiable intangible assets			$ 11,100
Medical Practice Innovations, Inc.
Restructuring Cost and Reserve [Line Items]
Ownership interest, percentage acquired			50.00%
CAMC Cancer Center
Restructuring Cost and Reserve [Line Items]
Ownership interest, percentage acquired				50.00%
Goodwill				$ 6,889
Payments to acquire interest in joint venture				14,414
Intangible assets				21,747
Revenues														1,768
Net income (loss)														$ 899
CAMC Cancer Center | Construction Permits
Restructuring Cost and Reserve [Line Items]
Intangible assets				$ 11,547