Acquisitions and other arrangements (Details) (USD $)	6 Months Ended		1 Months Ended			1 Months Ended				1 Months Ended	12 Months Ended		0 Months Ended	1 Months Ended		0 Months Ended		1 Months Ended		0 Months Ended			6 Months Ended		6 Months Ended		6 Months Ended				1 Months Ended			1 Months Ended			0 Months Ended			1 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Sep. 30, 2011 Professional services agreements entity	Mar. 31, 2012 License agreement item	Aug. 29, 2011 Radiation treatment center and other physician practices	Aug. 31, 2011 Radiation treatment center and other physician practices Non-compete agreement	Aug. 29, 2011 Radiation treatment center and other physician practices Non-compete agreement	Aug. 29, 2011 Radiation treatment center and other physician practices Trade names	Dec. 31, 2011 Physician practices and non-professional practice Florida and North Carolina	Mar. 31, 2012 Radiation oncology practice and urology groups Southwest Florida	Dec. 31, 2012 Radiation oncology practice and urology groups Southwest Florida	May 25, 2013 Radiation oncology practice and urology groups Southwest Florida	May 25, 2013 Radiation oncology practice and urology groups Non-compete agreement Southwest Florida	Mar. 31, 2012 Radiation oncology practice and urology groups Non-compete agreement Southwest Florida	Feb. 06, 2012 Radiation oncology practice North Carolina	May 25, 2013 Radiation oncology practice Southwest Florida center	Mar. 31, 2012 Radiation oncology practice Southwest Florida	Mar. 31, 2012 Urology groups Southwest Florida center	Dec. 28, 2012 Freestanding radiation facility in West Palm Beach Florida Florida	Dec. 28, 2012 Freestanding radiation facility in West Palm Beach Florida Non-compete agreement Florida	Dec. 31, 2012 Physician practices Arizona, California and Florida	Jun. 30, 2013 Physician practices Arizona and North Carolina	Jun. 30, 2013 Joint venture with radio surgery facility	Jun. 30, 2013 Casa Grande, Arizona joint venture Arizona	Jun. 30, 2013 Casa Grande, Arizona joint venture Non-compete agreement Arizona	Jun. 30, 2013 Casa Grande, Arizona joint venture Trade names Arizona	Jun. 30, 2013 OnCure item center	Jun. 30, 2013 OnCure Stalking horse investment agreement	Jul. 31, 2013 Woonsocket, Rhode Island joint venture Rhode Island Subsequent event	Jul. 31, 2013 Tiajuana, Mexico radiation treatment center Mexico Subsequent event	Nov. 30, 2012 All acquired operating entities Argentina	Nov. 30, 2011 All acquired operating entities Argentina installment	Nov. 04, 2011 All acquired operating entities Argentina	Nov. 30, 2011 All acquired operating entities Non-compete agreement Argentina	Nov. 04, 2011 All acquired operating entities Non-compete agreement Argentina	Nov. 04, 2011 All acquired operating entities Trade names Argentina	Nov. 04, 2011 Acquired operating entity one Argentina center	Nov. 04, 2011 Acquired operating entity two Argentina center	Nov. 04, 2011 Acquired operating entity three Argentina center	Apr. 30, 2012 Acquired operating entity four North Carolina center	Dec. 31, 2011 Acquired operating entity four North Carolina center	Apr. 16, 2012 Acquired operating entity four North Carolina	Dec. 22, 2011 Acquired operating entity four North Carolina
Acquisitions
Number of radiation oncology practices acquired																5																					1	3	1
Total purchase price					$ 9,600,000				$ 400,000	$ 27,600,000		$ 28,500,000			$ 900,000		$ 26,000,000	$ 1,600,000	$ 1,100,000		$ 1,700,000	$ 100,000						$ 125,000,000	$ 1,500,000	$ 1,600,000	$ 1,400,000		$ 7,400,000										$ 6,300,000
Purchase price allocated to tangible assets				4,300,000	3,300,000				400,000	7,800,000		10,400,000			800,000				300,000		1,700,000	100,000		2,000,000									3,700,000										1,200,000
Purchase price allocated to cash																																	600,000
Purchase price allocated to intangible assets							300,000	300,000					1,900,000	6,100,000						200,000					400,000	1,800,000									200,000	200,000
Amortization period of acquired intangible assets						5 years							5 years	5 years						2 years					7 years									5 years
Purchase price allocated to goodwill					5,700,000					13,700,000		16,200,000			100,000				800,000					5,000,000							(1,400,000)		8,100,000										6,400,000
Interest in an unconsolidated joint venture sold (as a percent)																							45.00%
Interest in an unconsolidated joint venture sold																							1,500,000
Purchase price allocated to current liabilities																			200,000
Purchase price allocated to contingent, earn-out provision																																											800,000
Purchase price allocated to liabilities																																	3,400,000										100,000
Purchase price allocated to assumed debt										5,700,000		8,700,000																82,500,000
Initial deposit funded into an escrow account	5,001,000																											5,000,000
Number of medical groups to whom acquiree provides services																											11
Purchase price allocated to redeemable noncontrolling interests																								4,200,000							(1,400,000)		1,400,000
Amount adjusted to the purchase option as an expense in the fair value adjustment of the noncontrolling interests-redeemable																															200,000
Number of sites operated under contractual arrangement			2
Capital lease obligations	78,000	696,000								5,700,000
Ownership interest purchased (as a percent)																			50.00%					55.00%					38.00%								80.00%	80.00%	96.00%
Number of treatment center acquired																																								1	2
Purchase price of additional assets acquired																																										400,000
Cash paid for acquisition										21,900,000		17,700,000												5,000,000				42,500,000					2,100,000
Seller financing note for acquisition												2,100,000																					4,000,000
Number of monthly installments in which the seller financing notes are payable																																24
Purchase option for acquisition																																	1,300,000
Initial term of license agreement				10 years
Renewal period of license agreement				5 years
Number of renewal options for license agreement				3
Number of urology groups acquired																		2
Number of radiation oncology treatment centers owned by the acquiree																											34
Total amortization expense											900,000
Estimated future amortization expense for the acquired preliminary amortizable intangible assets
2013											1,220,000
2014											1,220,000
2015											1,220,000
2016											1,220,000
2017											$ 305,000