CONSOLIDATED STATEMENT OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Operating activities:
Net income	$ 6,976	$ 7,043
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	14,158	13,401
Stock-based compensation expense	3,028	3,690
Excess tax benefit from exercised stock options	(3,021)	(5,516)
Deferred income taxes	(850)	(1,000)
Increase in allowance for doubtful debts	1,758	1,265
Change in fair value of contingent consideration	43
Loss on disposal of fixed assets	46	2
Changes in operating assets and liabilities:
Accounts receivable	202	5,601
Prepaid expenses	169	(6,240)
Prepaid income taxes	(2,861)	1,957
Other current assets	(371)	337
Other assets	(34)	(152)
Accounts payable, accrued expenses and other liabilities	(5,863)	(8,280)
Estimated liability for appeals	2,573	3,390
Net cash provided by operating activities	15,953	15,498
Investing activities:
Purchases of property and equipment	(9,100)	(8,522)
Acquisitions, net		(1,605)
Investment in capitalized software	(734)	(431)
Net cash used in investing activities	(9,834)	(10,558)
Financing activities:
Repayment of term loan	(8,750)	(4,375)
Payments on contingent consideration		(250)
Payments on capital lease obligations	(287)	(154)
Proceeds from exercise of stock options	5,375	5,702
Payments of tax withholdings on behalf of employees for net-share settlement for stock-based compensation	(1,483)	(1,122)
Excess tax benefit from exercised stock options	3,021	5,516
Net cash (used in)/provided by financing activities	(2,124)	5,317
Net increase in cash and cash equivalents	3,995	10,257
Cash and cash equivalents at beginning of period	135,227	97,003
Cash and cash equivalents at end of period	139,222	107,260
Supplemental disclosure of cash flow information:
Cash paid for income taxes	11,837	3,530
Cash paid for interest	2,879	3,736
Supplemental disclosure of noncash investing activities:
Accrued property and equipment purchases	1,128	1,495
Equipment purchased through capital leases	$ 1,626	$ 185