Segment Information (Summary of Goodwill by Segment) (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Summary of goodwill by segment
Beginning balance	$ 56,975	$ 56,493
Goodwill acquired during the period	0	0
Impairment charges	0	0
Adjustments to goodwill during the period	0	482
Ending balance	56,975	56,975
Gross goodwill	231,219
Accumulated impairment charges	(174,244)
Imaging
Summary of goodwill by segment
Beginning balance	42,166	41,684
Goodwill acquired during the period	0	0
Impairment charges	0	0
Adjustments to goodwill during the period	0	482
Ending balance	42,166	42,166
Gross goodwill	196,508
Accumulated impairment charges	(154,342)
Radiation Oncology
Summary of goodwill by segment
Beginning balance	14,809	14,809
Goodwill acquired during the period	0	0
Impairment charges	0	0
Adjustments to goodwill during the period	0	0
Ending balance	14,809	14,809
Gross goodwill	34,711
Accumulated impairment charges	(19,902)
Corporate / Other
Summary of goodwill by segment
Beginning balance	0	0
Goodwill acquired during the period	0	0
Impairment charges	0	0
Adjustments to goodwill during the period	0	0
Ending balance	0	0
Gross goodwill	0
Accumulated impairment charges	$ 0