CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010
Cash flows from operating activities:
Net income	$ 21,644	$ 13,764
Adjustments to reconcile net income to net cash used in operating activities:
(Gain) loss on disposal of assets and auction rate securities	(45)	232
Reduction of seller notes and earnouts	(281)
Provision for bad debts	10,891	8,142
Provision for deferred income taxes	(343)	4,052
Depreciation and amortization	14,988	8,771
Amortization of debt issuance costs	1,607	911
Compensation expense on restricted stock	3,874	4,356
Changes in assets and liabilities, net of effects of acquired companies:
Accounts receivable	(12,779)	(7,685)
Inventories	(4,181)	(3,510)
Prepaid expenses, other current assets, and income taxes	3,926	(8,928)
Accounts payable	(7,583)	(2,747)
Accrued expenses and accrued interest payable	(1,854)	(2,868)
Accrued compensation related costs	(19,332)	(9,340)
Other	106	1,110
Net cash provided by in operating activities	10,638	6,260
Cash flows from investing activities:
Purchase of property, plant and equipment (net of acquisitions)	(13,630)	(13,740)
Purchase of equipment leased to third parties under operating leases	(1,639)
Acquisitions and contingent purchase price (net of cash acquired)	(6,064)	(6,784)
Proceeds from sale of property, plant and equipment	94	2
Proceeds from sale of auction rate securities		1,518
Net cash used in investing activities	(21,239)	(19,004)
Cash flows from financing activities:
Borrowings under revolving credit agreement	10,000
Repayment under revolving credit agreement	(10,000)
Repayment of term loan	(1,500)	(1,201)
Repayment of long-term debt	(2,119)	(1,713)
Deferred financing costs	(4,230)
Excess tax benefit from stock-based compensation	1,095	1,220
Proceeds from issuance of common stock	573	2,013
Net cash (used in) provided by financing activities	(6,181)	319
Decrease in cash and cash equivalents	(16,782)	(12,425)
Cash and cash equivalents, at beginning of period	36,308	84,558
Cash and cash equivalents, at end of period	$ 19,526	$ 72,133