Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating activities:
Net income	$ 24,527	$ 13,947	$ 39,997
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of property and equipment	30,328	32,864	31,360
Amortization of intangible assets	20,270	20,734	23,631
Amortization of deferred financing costs	2,084	2,084	3,077
Stock-based compensation expense	14,297	13,356	11,997
Excess tax benefit from exercised stock options	(1,569)	(1,795)	(5,233)
Deferred income taxes	(14,020)	(12,290)	(4,354)
Loss on disposal of fixed assets	$ 84	219	431
Change in fair value of contingent consideration		(517)	35
Changes in operating assets and liabilities:
Accounts receivable	$ (12,045)	14,625	(14,956)
Prepaid expenses	549	1,132	1,341
Prepaid income taxes	6,711	3,445	(1,559)
Other current assets	(412)	(2,150)	(172)
Other assets	10	$ 121	$ 28
Income taxes payable	3,873
Accounts payable, accrued expenses and other liabilities	(250)	$ 18,039	$ 1,050
Estimated liability for appeals	(3,721)	(5,053)	14,508
Net cash provided by operating activities	70,716	98,761	101,181
Investing activities:
Purchases of land, property and equipment	(8,620)	(22,687)	(22,127)
Investment in capitalized software	$ (3,197)	$ (3,514)	(3,656)
Investment in common stock			(500)
Net cash used in investing activities	$ (11,817)	$ (26,201)	(26,283)
Financing activities:
Repayment of revolving credit facility		(35,000)	(95,000)
Proceeds from exercise of stock options	$ 4,187	4,110	9,260
Excess tax benefit from exercised stock options	1,569	1,795	5,233
Payments of tax withholdings on behalf of employees for net-share settlement for stock-based compensation	(1,029)	(1,658)	(1,922)
Payments on capital lease obligations	$ (1,132)	(1,629)	$ (1,711)
Payments on contingent consideration		$ (428)
Purchases of treasury stock	$ (50,000)		$ (25,000)
Repayment of term loan			(8,750)
Proceeds from revolving credit facility			4,046
Payment of financing fees related to revolving credit facility			(2,915)
Net cash used in financing activities	$ (46,405)	$ (32,810)	(116,759)
Net increase (decrease) in cash and cash equivalents	12,494	39,750	(41,861)
Cash and cash equivalents at beginning of year	133,116	93,366	135,227
Cash and cash equivalents at end of year	145,610	133,116	93,366
Supplemental disclosure of cash flow information:
Cash paid for income taxes	22,878	21,144	34,922
Cash paid for interest	5,694	4,458	9,520
Supplemental disclosure of noncash activities:
Accrued property and equipment purchases	$ 729	1,610	1,725
Equipment purchased through capital leases		$ 20	$ 2,401