Investments in Unconsolidated Investees (Balance Sheet Data) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Alliance-HNI, LLC and Subsidiaries
Schedule of financial data of unconsolidated investees, Balance Sheet Data
Current assets	$ 3,472	$ 4,650
Noncurrent assets	10,059	9,732
Current liabilities	2,536	2,810
Noncurrent liabilities	3,613	2,757
Unconsolidated Investees, Including Alliance-HNI, LLC and Subsidiaries and Austin Cyberknife
Schedule of financial data of unconsolidated investees, Balance Sheet Data
Current assets	7,195	7,188
Noncurrent assets	11,027	11,058
Current liabilities	3,494	3,569
Noncurrent liabilities	$ 3,864	$ 3,382