CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Operating activities:
Net income	$ 53,615	$ 38,999
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization expense	11,986	9,680
Stock-based compensation expense	7,336	4,522
Deferred income taxes	2,915	6,245
(Loss) gain on disposal of assets	4	(23)
Impairment of intangibles and other	1,123	81
Changes in operating assets and liabilities, net of acquisitions:
Receivables	(5,693)	(11,331)
Prepaid expenses and other assets	(7,489)	(3,859)
Prepaid income taxes	9,710	(4,879)
Accounts payable and accrued expenses	13,862	26,038
Income taxes payable	(313)	(3,499)
Net amounts due to/from governmental entities	(722)	(279)
Net cash provided by operating activities	86,334	61,695
Investing activities:
Purchases of property, building and equipment	(18,889)	(7,944)
Cash acquired from business combination, net of cash paid	9,070
Cash acquired from business combination, net of cash paid		(61,247)
Net cash used in investing activities	(9,819)	(69,191)
Financing activities:
Proceeds from line of credit	292,084	63,000
Payments on line of credit	(300,884)	(31,000)
Proceeds from employee stock purchase plan	1,015	776
Payments on debt	(196)	(192)
Payments on deferred financing fees	(1,881)	0
Noncontrolling interest distributions	(8,720)	(8,406)
Withholding taxes paid on stock-based compensation	(6,719)	(3,091)
Purchase of additional controlling interest	(412)	(184)
Sale of noncontrolling interest	3,322	251
Net cash provided by (used in) financing activities	(22,391)	21,154
Change in cash	54,124	13,658
Cash at beginning of period	2,849	3,264
Cash at end of period	56,973	16,922
Supplemental disclosures of cash flow information:
Interest paid	6,127	2,694
Income taxes paid	$ 2,929	$ 22,376