Supplemental Disclosures of Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Supplemental Disclosures of Cash Flow Information
Notes issued with acquisitions	$ 12	$ 327	$ 3,283
Liabilities assumed with acquisitions	298	122	885
Contingent consideration related to acquisitions			100
Liability for property and equipment	$ 36,744	$ 14,230
Notes issued to acquire non-consolidating interest			$ 3,399