Segment Information - Summary of Cash Used for Capital Expenditures by Segment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Segment Reporting Information [Line Items]
Cash used for capital expenditures			$ 26,382	$ 13,256
Operating Segments | Radiology
Segment Reporting Information [Line Items]
Cash used for capital expenditures	$ 5,865	$ 4,761	12,695	6,828
Operating Segments | Radiation Oncology
Segment Reporting Information [Line Items]
Cash used for capital expenditures	3,022	0	3,757	19
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Cash used for capital expenditures	$ 2,806	$ 2,741	$ 2,806	$ 6,409