Investments in Unconsolidated Investees - Combined Operating Results (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Schedule of financial data of unconsolidated investees, Combined Operating Results
Earnings from unconsolidated investee	$ 1,292	$ 1,242	$ 2,455	$ 2,240
Alliance-HNI, LLC and Subsidiaries
Schedule of financial data of unconsolidated investees, Combined Operating Results
Revenues	4,237	4,225	8,401	8,331
Expenses	2,201	2,266	4,605	4,821
Net income	2,036	1,959	3,796	3,510
Earnings from unconsolidated investee	1,018	979	1,898	1,755
Unconsolidated Investees, Including Alliance-HNI, LLC and Subsidiaries and Austin Cyberknife
Schedule of financial data of unconsolidated investees, Combined Operating Results
Revenues	6,469	6,765	13,106	13,196
Expenses	2,920	3,210	6,256	6,745
Net income	3,549	3,555	6,850	6,451
Earnings from unconsolidated investee	$ 1,292	$ 1,242	$ 2,455	$ 2,240