CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010
Cash flows from operating activities:
Net income	$ 37,056	$ 20,689
Adjustments to reconcile net income to net cash provided by operating activities:
(Gain) loss on disposal of assets and auction rate securities	(6)	704
Reduction of seller notes and earnouts	(321)	(93)
Provision for bad debts	17,291	12,213
Provision for deferred income taxes	(446)	4,052
Depreciation and amortization	22,852	13,242
Amortization of debt issuance costs	2,470	1,366
Compensation expense on restricted stock	6,014	5,920
Changes in assets and liabilities, net of effects of acquired companies:
Accounts receivable	(23,551)	(10,038)
Inventories	(11,584)	(7,604)
Prepaid expenses, other current assets, and income taxes	7,640	(7,755)
Accounts payable	(6,757)	(1,154)
Accrued expenses and accrued interest payable	2,142	9,356
Accrued compensation related costs	(19,816)	(5,865)
Other	2,166	2,353
Net cash provided by operating activities	35,150	37,386
Cash flows from investing activities:
Purchase of property, plant and equipment (net of acquisitions)	(18,879)	(19,743)
Purchase of equipment leased to third parties under operating leases	(2,875)
Acquisitions and contingent purchase price (net of cash acquired)	(10,868)	(9,385)
Proceeds from sale of property, plant and equipment	94	72
Proceeds from sale of marketable securities		6,494
Net cash used in investing activities	(32,528)	(22,562)
Cash flows from financing activities:
Borrowings under revolving credit agreement	10,000
Repayment under revolving credit agreement	(10,000)
Repayment of term loan	(2,250)	(1,731)
Scheduled repayment of seller's notes	(2,561)	(1,934)
Repayment of line of credit		(3,657)
Deferred financing costs	(4,230)
Excess tax benefit from stock-based compensation	975	1,536
Proceeds from issuance of common stock	573	2,013
Net cash used in financing activities	(7,493)	(3,773)
(Decrease) increase in cash and cash equivalents	(4,871)	11,051
Cash and cash equivalents, at beginning of period	36,308	84,558
Cash and cash equivalents, at end of period	$ 31,437	$ 95,609