Segment Information (Summary of Goodwill by Segment) (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2013	Dec. 31, 2012
Summary of goodwill by segment
Beginning balance	$ 56,493	$ 56,493
Goodwill acquired during the period	0	0
Impairment charges	0	0
Adjustments to goodwill during the period	0	0
Gross goodwill	230,737
Accumulated impairment charges	(174,244)
Ending balance	56,493	56,493
Imaging [Member]
Summary of goodwill by segment
Beginning balance	41,684	41,684
Goodwill acquired during the period	0	0
Impairment charges	0	0
Adjustments to goodwill during the period	0	0
Gross goodwill	196,026
Accumulated impairment charges	(154,342)
Ending balance	41,684	41,684
Radiation Oncology [Member]
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
Gross goodwill	34,711
Accumulated impairment charges	(19,902)
Ending balance	14,809	14,809
Corporate / Other [Member]
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
Gross goodwill	0
Accumulated impairment charges	0
Ending balance	$ 0	$ 0