COMBINED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 12,392	$ 8,012	$ 8,388
Depreciation and amortization	4,607	3,856	3,703
Provision for bad debt	2,752	2,211	2,112
Deferred rent amortization	(122)	(112)	1,048
(Gain) loss on sale of equipment	(35)	195	125
Changes in operating assets and liabilities
Accounts receivable	(3,022)	(3,036)	(2,415)
Prepaid expenses and other current assets	(264)	(31)	748
Due from affiliates	1,293	(372)	4,110
Accounts payable, accrued expenses	(1,424)	878	517
Net cash provided by operating activities	16,177	11,601	18,336
CASH FLOWS FROM INVESTING ACTIVITIES
Purchase of property and equipment	(1,091)	(2,576)	(2,495)
Purchase of imaging facilities	(2,935)		(133)
Proceeds from sale of equipment	35		305
Net cash used in investing activities	(3,991)	(2,576)	(2,323)
CASH FLOWS FROM FINANCING ACTIVITIES
Principal payments on notes and leases payable	(2,976)	(2,764)	(2,576)
Contributions from partners	2,300
Distributions to partners	(11,821)	(5,980)	(13,085)
Net cash used in financing activities	(12,497)	(8,744)	(15,661)
NET (DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	(311)	281	352
CASH AND CASH EQUIVALENTS, beginning of period	2,089	1,808	1,456
CASH AND CASH EQUIVALENTS, end of period	1,778	2,089	1,808
Cash paid during the period for interest	$ 245	$ 381	$ 702