CONSOLIDATED STATEMENTS OF CASH FLOW (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Operating activities:
Net income and comprehensive income	$ 9,391	$ 17,396
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation expense	16,253	15,228
Amortization expense	11,335	14,934
Stock-based compensation expense	6,230	6,122
Excess tax benefit from exercised stock options	(854)	(4,244)
Deferred income taxes	(3,996)	(2,531)
Allowance for doubtful accounts	(6,462)	6,314
Change in fair value of contingent consideration	11	20
Loss on disposal of fixed assets	4	184
Changes in assets and liabilities:
Accounts receivable	13,645	(16,772)
Prepaid expenses	2,032	1,878
Prepaid income taxes	7,311	(2,742)
Other current assets	19	(73)
Other assets	(45)	7
Accounts payable, accrued expenses and other liabilities	(1,193)	(7,011)
Estimated liability for appeals	(6,132)	7,161
Net cash provided by operating activities	47,549	35,871
Investing activities:
Purchases of property and equipment	(10,315)	(12,734)
Investment in common stock		(500)
Investment in capitalized software	(1,309)	(1,996)
Net cash used in investing activities	(11,624)	(15,230)
Financing activities:
Financing related to revolving credit facility		(2,915)
Repayment of term loan		(8,750)
Repayment of revolving credit facility	(35,000)	(25,000)
Payments on contingent consideration	(428)
Payments on capital lease obligations	(826)	(838)
Proceeds from exercise of stock options	3,076	6,309
Payments of tax withholdings on behalf of employees for net-share settlement for stock-based compensation	(1,088)	(1,498)
Excess tax benefit from exercised stock options	854	4,244
Proceeds from revolving credit facility		4,046
Net cash (used in ) /provided by financing activities	(33,412)	(24,402)
Net increase (decrease) in cash and cash equivalents	2,513	(3,761)
Cash and cash equivalents at beginning of year	93,366	135,227
Cash and cash equivalents at end of year	95,879	131,466
Supplemental disclosure of cash flow information:
Cash paid for income taxes	3,503	19,881
Cash paid for interest	2,538	4,308
Supplemental disclosure of noncash investing activities:
Accrued property and equipment purchases	1,633	1,655
Equipment purchased through capital leases	$ 20	$ 2,196