CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
CASH FLOWS FROM OPERATING ACTIVITIES
Net loss	$ (1,366)	$ (152)
Depreciation and amortization	14,760	14,892
Provision for bad debt	6,822	6,484
Equity in earnings of joint ventures	(1,206)	(1,262)
Distributions from joint ventures	1,921	1,575
Deferred rent amortization	433	288
Amortization of deferred financing cost	457	602
Amortization of bond discount	400	234
Loss on sale and disposal of equipment	170	24
Amortization of cash flow hedge		276
Stock-based compensation	952	1,175
Changes in operating assets and liabilities, net of assets acquired and liabilities assumed in purchase transactions:
Accounts receivable	(11,782)	(12,023)
Other current assets	(5,099)	(683)
Other assets	(105)	(64)
Deferred revenue	3	86
Accounts payable, accrued expenses and other	8,861	3,979
Net cash provided by operating activities	15,221	15,431
CASH FLOWS FROM INVESTING ACTIVITIES
Purchase of imaging facilities	(3,625)	(580)
Purchase of property and equipment	(12,926)	(13,962)
Proceeds from sale of equipment	270	410
Proceeds from sale of noncontrolling interests	2,640
Proceeds from sale of imaging facilities		2,300
Purchase of equity interest in joint ventures	(724)	(920)
Net cash used in investing activities	(14,365)	(12,752)
CASH FLOWS FROM FINANCING ACTIVITIES
Principal payments on notes and leases payable	(2,697)	(4,479)
Proceeds from, net of payments on, line of credit	1,500	2,700
Payments to counterparties of interest rate swaps, net of amounts received		(1,500)
Distributions to noncontrolling interests		(26)
Proceeds from issuance of common stock upon exercise of options/warrants	469
Net cash used in financing activities	(728)	(3,305)
EFFECT OF EXCHANGE RATE CHANGES ON CASH	(59)	5
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	69	(621)
CASH AND CASH EQUIVALENTS, beginning of period	362	2,455
CASH AND CASH EQUIVALENTS, end of period	431	1,834
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION
Cash paid during the period for interest	$ 5,531	$ 6,841